Merlin Magic

…we will not care about what we do not recognize.

~Tim Beatley

I have spent a lifetime trying to learn about the world around me. Not about the financial sector, or cars, or electricity (all of these, I now realize, might actually have come in handy), but about the natural world, the plants and animals that live around me. It is just who I am, what interests me. In his essay on the importance of fostering a connection to the natural world, Tim Beatley starts by saying – What we choose to name and the names we choose to remember, for the places, people and things around us, says a great deal about what is important to us. I have spent a lot of years trying to help people learn the names of things in nature and have come to realize that it takes time. On many of my field trips, I remember being frustrated when people could not remember the name of some interesting creature we had just observed. I finally realized that it often requires that the person is prepared to receive that information and that they want to learn it. In his 2013 article, Dr. Beatley offers numerous suggestions on how we can help foster a connection to nature through helping people become better acquainted with their natural surroundings. He also recognizes that new technologies and applications may of course help us here as well. I-birds and I-trees that make it easier and quicker to identify birds and trees. Well, it is happening…

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The Cornell Lab of Ornithology launched its popular Merlin App in 2014. It is billed as an online field guide assistant for beginning and intermediate birders. The app asks you a series of questions about the bird you just saw (such as the color, size, and behavior), much like an experienced birder would if they were trying to help you identify it. To be honest, I never downloaded that app, figuring I had enough experience to use field guides and figure most birds out on my own. But, late last year, a new feature was added – the Photo ID portion of the app. I heard about it from a couple of people I know, saw a review online by a fantastic wildlife photographer I follow, and then had a friend post about it on her blog. I decided to check it out and downloaded the free app to my iPhone (also available for Android devices; being developed for laptops and other non-mobile devices)..

Details on how it has been developed are mentioned in a press release about the launch of the Photo ID portion of the app last month. The app claims to have about a 90% accuracy rate in identifying over 600 species of North American birds. I decided to give it a test drive and see for myself.

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The app has a simple and elegant design. You simply click the Photo ID tab and either take a photo or choose a photo from your files.

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I used an image of a sharp-shinned hawk I had taken a couple of years ago at Roads End. Even good birders struggle with identifying this species from its larger cousin, the Cooper’s hawk. You zoom the image in until it roughly fills the box…

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The app pulls information off your photo as to date and location. I had to fill in the location information since this was a photo I uploaded from a file on my computer, not one directly from my camera. Once I had added Pittsboro as the location, the app can compare my image to its database of images (I think it has at least 1000 images of each species covered) and then gives you an identification.

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Boom! It got it right. It even gives alternative possibilities if you scroll down in the app. This can be very important for some species where confusion is likely (like this one), or if the photo you use is not that great.

I soon realized I didn’t need to transfer images from my laptop to my phone for identification, I could simply click the Take Photo tab and take a picture of my laptop screen with my phone and use that image. So, here is another. For these next few images, try to identify the species before you see the Merlin App identification. As this progresses, I intentionally use pictures of lesser quality, those that I normally would delete from my files, to see how the app performs.

This first one is a photo of a pretty nondescript species (taken with my phone of a fairly good shot on file on my laptop, note some of the squiggly computer screen lines in the photo).

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And here is what the app said it was…

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Indeed, it is a female of a warbler, the common yellowthroat. The app gives you multiple images of each species so I swiped through and found an image of a female (turns out my image is better than the one they have on file). In all fairness, I knew what that bird was. If I hadn’t, it might have been tough for me to figure out based on the images the app provided. But, the beauty of this is it gives you a place to start in terms of looking up your bird in a field guide (book or online).

Here’s another, a bird I photographed with my iPhone as it was getting dark in the Boundary Waters last October. This bird landed next to us on a boulder and walked around, allowing me to get a good look, and this crummy photo. I did not know what species this was, as I had never seen this one before. Once we got back home, I identified it using my field guides, but the app got it on the first try.

BWCA shorebird

Grainy iPhone photo of an unknown shorebird in Minnesota in October

An American golden plover, a new species for me. Once again, I had to swipe through the images to find the shot of the bird I saw in its non-breeding plumage.

Here are three more just for fun…

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Black bird in NC mountains

Merlin gave me the wrong answer the first time, calling this a fish crow. I zoomed in even more, tight on the bill, which is diagnostic of this species, and it got it right (did you?).

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Notice that fish crow is the second option this time (other options are listed below the primary choice in the app). I found that zooming in and out did make a difference on some species. The first time I tried the next photo, I was in very tight on the whole bird and it gave me red-headed woodpecker as the answer.

black throated blue

Mystery bird in NC mountains in May

Zoom in on the photo and see if you can identify it. I edited my photo on my next try by backing off a little and, this time, Merlin was right.

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It is a male black-throated blue throwing its head back in song.

I tried a range of images of a variety of species differing in photo quality. They were all images where I knew the identification of the bird from other, better images, taken at that same time. Merlin did not get a black-capped petrel or the glaucous gull from the pelagic birding trip I took last winter. Turns out that species of petrel is not one in the database as yet, and the gull was misidentified as an Iceland gull. And, it surprisingly gave me a related species (correct species as second choice) on the following really terrible image I used from the Christmas bird count this year.

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Mystery bird from Christmas bird count at Pungo

Guesses?

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Yes, a blue-gray gnatcatcher, a species not often seen in winter in these parts (but also not an extreme rarity). Interesting that it gave me a species from the southwestern United States even though I put in the location information for our count. But, to get any gnatcatcher from that photo is pretty impressive if you ask me. The photo does not show the flitting behavior, nor the relatively small size I witnessed while watching the bird in person.

Overall, I think this app is a great tool for anyone that wants to identify the birds they photograph. I get asked a lot of questions about bird identification (which I enjoy tying to answer, by the way), but I will also be recommending this app for all those folks from now on. Give it a try, download Merlin and have some fun. While you are at it, I recommend making a donation to the Cornell Lab of Ornithology to help them continue to produce valuable information for all us folks trying to learn about, and conserve, the birds around us ( I just did).

Refuge Renewal

In such surroundings – occasional as our visits may be – we can achieve that kind of physical and spiritual renewal that comes alone from the wonder of the natural world.

~Laurence Rockefeller

It is the season of renewal for me, the season of experiencing some of the wild spectacles of this place I call home. I had a trip this past week to Pocosin Lakes and Mattamuskeet National Wildlife Refuges and, though we ended up leaving a bit early due to the predicted winter storm, it was still a refreshing reminder of why these places are so important – important to the amazing wildlife that can be found there, and important to those of us lucky enough to spend time in them.

Great blue heron

Great blue heron walking in shallows along causeway (click photos to enlarge)

I stopped by the Pungo Unit on my way down Wednesday. Very quiet and the roads were pretty muddy. We started our tour at sunrise the next morning at Lake Mattamuskeet. There are relatively few birds out along the causeway this year, due to the wet year and resulting high lake levels, and the decline in the submerged aquatic vegetation (see recent Wildlife in North Carolina magazine article). You can still usually find a couple of birds near the south end of the causeway, especially some waders like the great blue heron above. I love the textures of their feathers, which seem even more prominent in cold weather.

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Black-crowned night heron adult

I always look for a heron or black-crowned night heron on the pilings in the marsh pool just inside the gate to the refuge, but they were empty. But, at the next pool, an adult night heron was out in plain view, and was hunting. I have never seen a night heron at this particular pool in all the years I have been going to the refuge (and haven’t seen much else here the past couple of years since the Phragmites grass has taken over the edge of the pool).

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Night heron strikes and catches a small fish (note nictitating membrane to protect eye)

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Nothing like a good scratch after a meal

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The red eye of an adult black-crowned night heron is spectacular

Their red eye is stunning in sunlight. Young black-crowned night herons have yellow eyes, that gradually change to orange, and then red as they mature. Though many species of birds show a change in eye color from young to adult, no one seems sure what the evolutionary significance of this may be.

Bald eagle immature

Immature bald eagle

Among the many birds we saw, there were the usual bald eagles perched along the edges of the lake and marshes scanning the areas for weakened waterfowl that make an easy meal. At one point, we had two immature eagles and a red-tailed hawk all soar out over us.

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The eagles engaged in aerial combat

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One eagle rolled over, extending its talons

Suddenly, the two eagles started to chase one another and were soon performing some serious acrobatics. This may be a territorial battle, or simply their form of play, I’m not sure. Almost as quickly as it had started, it was over. We saw some more of this over at Pungo the next day involving three eagles, two adults chasing one juvenile through the woods.

Anhinga sunning

An anhinga sunning itself

I had seen an anhinga in the Mattamuskeet canals on a visit in December, so I was looking for it again. We found it sunning itself in a tree across the canal from the lodge. Interestingly, this spot used to be the best place on the refuge to see black-crowned night herons (especially juveniles), but the past two winters they have been scarce.

Anhinga swimming

Anhinga, often called the snakebird, for its swimming style

As we admired the anhinga through my scope, another one came swimming down the canal. I think this is the first time I have ever seen two at once on the refuge.

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White ibis landing in marsh

We continued looking for wildlife throughout much of the day, with many of the usual suspects being observed. We found almost 100 white ibis feeding in a field at Lake Landing, and felt lucky to see a group of American white pelicans soaring over us. We also had a couple of good warbler sightings – a cooperative common yellowthroat male and an orange-crowned warbler. Overall waterfowl numbers seemed low, but there is still enough diversity to get some good looks and decent photos.

Photo blind

New photo blind at Mattamuskeet

It wasn’t until late in the day we discovered the new photo blind on the refuge. It is located along Hwy 94, between the entrance and exit points of Wildlife Drive. Kudos to those responsible – it is a great design with good viewing ports covered by camouflage netting. When we drove up, there were several species of waterfowl just off the front of the blind. They swam off as we walked in, but I think if you spend some time in this spot, you could get some good results once the birds return (you can’t really sneak in without nearby birds seeing you; bring a seat or bucket if you plan to spend time in it). I look forward to returning on a future trip. I hope other public land managers will consider putting up similar structures. This one was funded, at least in part, by a grant from the North American Nature Photography Association.

Swan taking off in Marsh A

Tundra swan taking off

That afternoon, we headed over to the Pungo Unit to hopefully enjoy the evening show of swans and snow geese returning to Pungo Lake. As I mentioned in my last post, the swans have been amazing this winter, and they did not disappoint.

Snow geese overhead

Snow geese flying high overhead

In our almost two days on the Pungo Unit, we did see the elusive snow geese flying far off the refuge to feed, returning a relatively short time later. A few thousand (of the estimated 15-20,000 birds) flew over us as walked down North lake Drive on our second day out, coming in at a very high altitude as they approached the lake. They continue to be unpredictable in their movements, although I think they will be closer to the refuge roads once some of remaining corn on refuge lands is knocked down (I expect that to happen very soon).

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A young bear jumps over a drainage ditch

This has been a strange winter for the black bears at Pungo. We saw what seemed the usual number on our trip in mid-December (8, as I recall). But since then, sightings have been few and far between, including being skunked in bear sightings on our Christmas Bird Count the last week of December (maybe the only time that has happened in over 30 years of doing that count). On this trip, I saw three (a sow and two yearlings) my first afternoon, and then we saw only three others in two days – one in the front fields coming out of the corn at sunrise, one feeding in corn and one cruising across the corn fields along North Lake Road.

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What looks like a bear play area in the woods

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Bark stripped from a pawpaw tree by a bear

There seems to be plenty of fresh bear sign in the woods and along the edges of the fields (although not as much scat in the roads as usual), so I am not quite sure what is going on. I think there may be increased hunting pressure on local bears at the edge of the refuge and this may be altering their behavior and making them more secretive, as well as reducing their numbers with greater numbers of bears that venture off the refuge being taken.

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Sunset with swans returning to the refuge

It is still a magical place, especially at sunrise and sunset. The swans fill the evening sky with magical sounds and the graceful lines of returning birds. I’ll leave you with a video clip from our sunrise at Pungo and the swans that make this refuge such a place of renewal for myself and so many others that spend any time in it.

Red-shoulders

The sparrow flying behind the hawk thinks the hawk is fleeing.

~Japanese proverb

Red-shouldered hawk

Red-shouldered hawk at the NC Botanical Garden (click photos to enlarge)

Last Saturday, I had the opportunity to work with my friend, Mary, to provide an introductory bird photography class at the NC Botanical Garden (NCBG) in Chapel Hill. It was next to the last in a series of programs that were part of the Saving Our Birds program initiative the Garden has sponsored this year. For part of the program, we went outside into the brisk morning air, spending time in their very active bird blind area, and the rest of the time walking around the native plant display gardens, looking for birds to photograph. The highlight of the day was a beautiful red-shouldered hawk (Buteo lineatus), that was most obliging to our group.

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Back view of red-shouldered hawk

Red-shouldered hawks are medium-sized buteos (soaring hawks) easily recognized by their rusty, barred breast, and the bold black-and-white bands on their tail. Immature birds are a bit tougher to identify – their tail is dark brown with several narrow brown bars and they have a pale breast with thick dark streaking that somewhat resembles several other common raptors. The area around the display gardens at NCBG has been home to at least one pair of red-shouldered hawks for several years. They seem well-adjusted to the comings and goings of people at the Garden. This one was perched in a tree near the building complex for much of the morning and early afternoon. This allowed our class to photograph it from many angles so we could try to avoid the cluster of twigs and branches that surrounded the hawk. The light was perfect and the bird cooperative, a perfect scenario for photographers.

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They have rusty red coloration on the feathers on their shoulders (lesser upperwing coverts)

After the program, I went back out to the tree with my 500mm lens and spent over an hour with this beautiful bird, watching it, and taking way too many photos. I appreciated the chance to simply observe this raptor and take notice of its many traits and adaptations. The light was so rich that I could clearly see the reddish colors of their shoulder feathers that gives this species its common name.

red-shouldered hawk open eye

“Eyes like a hawk” means someone with exceptional vision

The feature that stood out for me was its eyes…so intense, so fierce. According to several online resources, raptors can see anywhere from four to eight times better than the average human. This is accomplished by a couple of adaptations. The eyes of a hawk are proportionally larger than a human eye, occupying some 10-15% of the weight of the head, compared to about 1% in humans. Hawks also have more concentrated areas of rods and cones than we do, giving them higher resolution (sharper) vision. They have two fovea (one central and one peripheral) compared to just a central one in humans. The fovea is the spot on the back of our eye with the highest concentration of rods and cones.

Like us, raptors have binocular vision, with the eyes placed facing forward on the head. This allows them (and us) to judge distances better and to focus on something with both eyes at once. Hawks can also reportedly perceive more colors than us, and can also see ultraviolet light (which may help in tracing urine trails of small mammals in vegetation).

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The nictitating membrane sweeps from front to back

A bird also have some extra protection for their eye, a third eyelid called a nictitating membrane. This is a thin, translucent membrane that is used for protecting, lubricating, and cleaning the eye. A bird can still see when this membrane covers the eye, whereas we cannot when our eyelid closes. Birds also have a moveable upper and lower eyelid. The upper eyelid moves downward when a bird blinks. The lower eyelid moves upward when a bird sleeps. The nictitating membrane moves horizontally across a bird’s eye, sweeping from front to back. Based on my afternoon of hawk-watching, birds must use the nictitating membrane much more frequently than they do their upper eyelid. I took about 680 images (see what I mean, way too many) of the hawk that afternoon and captured 6 sweeps with the nictitating membrane, and no blinks with the upper eyelid.

red-shouldered hawk talons

Talons are long, sharp claws

Red-shouldered hawks feed on a variety of prey including reptiles, amphibians, and small mammals. Their feet and talons are used to capture and hold struggling prey.

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A hawk profile showing the sharp hooked beak

Hawks have sharp, hooked beaks used to grab prey, pull off fur, skin, or feathers, and tear the meat into bite-sized chunks. I kept hoping this hawk would sail down to capture something, but all it did was occasionally focus on some unseen item of interest in the vegetation around me.

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Scratching an itch

Hawk preening

Preening

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Checking out the back side

In addition to watching everything around it, the hawk occasionally did what all birds spend a lot of time doing – preening its beautiful feathers. Preening is accomplished by running the feathers through the talons or beak, gently pulling and realigning feathers for their optimum condition. This feather grooming can also help rid them of parasites, debris, and make them look their best for attracting mates. Mutual preening is also a part of the courtship ritual in some species.

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Hawk wing stretch

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The forward lean…

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…and let it fly!

I suppose it is fitting that toward the end of my time with my hawk, I witnessed the other end of the meal process, its elimination. After stretching its wings, the hawk leaned forward, raised its tail, and let fly with a white mass of bird poop that shot downward with considerable force. I often see them do this right before taking flight (it makes sense to lighten the load before take-off). Maybe this was just a commentary on my presence (or perhaps current events), but I decided to take the hint and pack up my camera and tripod and let the hawk go about its business for the rest of the afternoon. But I will be back and will photograph it again, hoping to capture some more behavior of this regal “garden” bird.

Sanctuary in the Swamp

…when life looks sandy and barren, is reduced to its lowest terms, we have no appetite, and it has no flavour, then let me visit such a swamp as this, deep and impenetrable, where the earth quakes for a rod around you at every step, with its open water where swallows skim and twitter…

~Henry David Thoreau, 1852

The words above were written over 150 years ago, but are still relevant to our times. For many people, the term swamp conjures up fearful images, or at least a place of snakes and mosquitoes, a place to avoid. For us, a swamp is a place of refuge, a place to quietly paddle with our thoughts, and to create a feeling of being connected to something wild and free. With all the difficult news these past few weeks, it seemed a great place to visit to recharge our tired batteries. We had three days with beautiful weather last week, so we headed to the Roanoke River for one of our favorite swamp outings – camping on the platforms run by the Roanoke River Partners.

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Our route covered about 30 miles and two camping platforms (click photos to enlarge)

We decided on an ambitious circular route that traversed about 30 miles of creeks and the river, with our longest paddle on the last day.

Launch site on Gardner Creek

The launch site on Gardner Creek

We launched around 1:30 pm at one of our favorite spots, Gardner Creek. Our route included two camping platforms, both of which we have used on previous trips – Barred Owl Roost and Three Sisters.

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Red maples add a fiery splash of color to the grays of the autumn swamp

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The calm water and blue sky added to the serenity of the swamp along Gardner Creek

The paddle out was gorgeous, with fall colors scattered among the grays of the trunks and exposed bottomland muds. Along the way, we started seeing and hearing a number of the wildlife species that would be our companions for the next three days – anhingas, wood ducks, Eastern bluebirds, and the ubiquitous barred owls.

Barred Owl Roost platform

Barred Owl Roost camping platform, one of our favorites

We covered the 6 miles or so to the camping platform in about 3 hours and had camp set up by 4:30 pm, just in time for the evening serenade of barred owls to begin. Their hooting calls mixed with the squawks and grunts of a nearby roosting colony of great blue herons that were coming in for the night. The Barred Owl Roost platform never fails to produce a cacophony of swamp sounds, especially from its namesake rulers of the night.

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Our solar-powered camp light casts a veil of light over our campsite

Darkness comes quickly this time of year, but the swamp at night is a magical place. We sat and listened to the many sounds as the day shift took refuge and the night shift came on duty. I walked out on along the tiny boardwalk and saw 5 crayfish in my flashlight beam, scurrying about in the clear water looking for something to eat, while no doubt hoping to avoid the talons of a hungry barred owl or the jaws of a cruising swamp fish.

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Sunrise in the swamp

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Twisted base of a tree near the platform

Owls called off and on all night and into the morning. Sunrise was chilly, and damp, with a heavy dew settling on our rain fly and anything else exposed on the platform or in the canoe. After a hearty breakfast, we loaded up and headed out for a long day of paddling.

morning light along Lower Deadwater Creek

Early morning light in Upper Deadwater Creek near the Barred Owl Roost platform

Once again, the soft light was beautiful as it eased through the gray pillars of tupelo gum and cypress trees. Patches of back lit colors pulled our eyes toward them as we paddled out toward the wider stretches of Devil’s Gut.

Cevil's Gut meets the Roanoke

Devil’s Gut meets the Roanoke

When you reach the Roanoke, it appears so vast, with the trees seeming to relinquish their hold on your attention, giving away that power to the brown waters and blue sky. The slight current helps your arm muscles and we proceeded to make good time as we headed down river about seven miles to the creek that would take us to the next platform.

River swamp

Riverine swamp along the Roanoke River

The river’s waters are much browner than Gardner Creek or some of the other tributaries to Devil’s Gut. It is wide with low flooded swamps on the north side and a variety of shorelines on the south, from high bluffs to flooded bottomland. All along our paddle you could see the high water mark left from the recent rains of Hurricane Matthew.

Paddling the Roanoke

Melissa paddling on the Roanoke River east of Jamesville (our rain fly drying in the sun in foreground)

Once we passed the scattered riverside homes and businesses of Jamesville, we saw few other signs of human presence for several miles. I like to paddle close to one of the shorelines in hopes of seeing wildlife, and to avoid any fishing boats that might be zipping up and down the river. But, there are places where your canoe may suddenly drag bottom in shallow mud flats that can extend far out into the river. The shallows often have dense growths of lily pads or other aquatic vegetation which attract fish, turtles, and other critters.

Muskrat feeding in river

Muskrat feeding in a water lily bed in the river (photo by Melissa Dowland)

At one such place, we spied something at the surface up ahead. It looked like a small mammal but seemed a bit odd in that its tail stuck out of the water at an angle. It dove, then resurfaced, tail again pointing skyward. It was a muskrat, apparently feeding on something in the shallows. It kept diving and coming back up in about the same place and didn’t seem to notice our canoe as we glided toward it. Melissa grabbed a few photos as I steered the boat. The muskrat finally saw us and disappeared with a quick splash.

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Huge osprey nest in bald cypress near the Three Sisters platform

When we turned up Broad Creek, we left the expanse of the river behind and, once more, the swamp seemed to reach out to our canoe and embrace us. The creeks are full of fish, both large and small (some very large ones startled us a time or two as they swirled and splashed right next to boat). We saw a few boats with fishermen, and most had multiple lines reaching for the depths. I asked one man what he was catching, “a few striped perch”, he replied. I was not familiar with that species, so he explained that is the local name for crappie. Missing from our swamp scene this time of year is another type of “fisherman”, the osprey. They have retreated south for the winter, but will return next March to show us humans how it is really done.

Sunset at Three Sisters platform

Sunset from our platform

The Three Sisters platform is situated along the edge of a creek instead of being nestled back in a swamp like Barred Owl Roost. There is a massive bald cypress next to the platform and a thicket of vines and shrubs along the creek edge that is apparently a preferred roosting spot for several of the local song birds, many of whom scolded us as we sipped a hot drink on the dock. The loud kerplunk of a beaver tail slap signaled this was also their territory, and at least one of them kept us on notice that he was watching us by continuing those warning slaps off and on throughout the night.

Cypress Creek scene

The intimate beauty of Cypress Creek

The next morning we headed over to Cypress Creek, a narrow, winding cut-through that connects Broad Creek back to the Roanoke River, and makes this such a great circular route. I was a little worried there might be downed trees blocking the path after the recent storm, but, it appears enough boaters use this cut that people tend to clear out any obstructions. You are paddling against the current here, but it was negligible on this outing (I have paddled it in high water when it was an exhausting challenge). All along the mud banks we could see tracks of animals such as deer, beaver, and raccoon.

Young raccoon in tree

Young raccoon on tree (photo by Melissa Dowland)

And suddenly, there was one of the track-makers, a young raccoon scrambling along a low branch out over the water. It quickly reached the trunk, climbed a bit and then stared back at us. After a couple of photos, we paddled on, hoping its next encounter with humans will be as peaceful.

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Swamp reflections

It is strange how we both are so quiet while paddling, often going 20 or 30 minutes without saying a word.I suppose it is part of the process of clearing your head and being connected to the place. It allows us to focus on our surroundings, to listen, and to see things we might otherwise miss. Perhaps there is something about the reflections of the forest in the dark waters that commands our silence and respect.

Gardner Creek

The swamp surrounds you in stillness and beauty

We finished our journey with a long paddle back up Devil’s Gut and Gardner Creek. Belted kingfishers rattled their disapproval and shared their acrobatic flying skills all along the way. More herons, more anhinga, a stunning bald eagle, another raccoon, and a surprise mink rounded out our wildlife sightings. We soon heard the road noise of Hwy 64, telling us we were back to civilization. But, for 3 days, our stresses and worries had been set aside by the silence and beauty of a sanctuary in a swamp. We will no doubt need to return in the near future for another dose of tranquility.

Species checklist:

Birds – Pied-billed grebe, anhinga, great blue heron, Canada goose, wood duck, mallard, bufflehead, hooded merganser, black vulture, turkey vulture, bald eagle, sharp-shinned hawk, red-shouldered hawk, red-tailed hawk, merlin, laughing gull, ring-billed gull, barred owl, belted kingfisher, red-bellied woodpecker, yellow-bellied sapsucker, downy woodpecker, Northern flicker, pileated woodpecker, Eastern phoebe, tree swallow, American crow, Carolina chickadee, tufted titmouse, white-breasted nuthatch, Carolina wren, golden-crowned kinglet, ruby-crowned kinglet, American robin, Eastern bluebird, Northern mockingbird, blue-headed vireo, Northern cardinal, red-winged blackbird, common grackle

Mammals – Raccoon, muskrat, beaver, gray squirrel, mink

Reptiles and amphibians – Painted turtle, yellow-bellied slider, Southern leopard frog

This is Nuts, Part 2

Each year insects heavily attack northern red oak acorns and destroy a large percentage of them, greatly reducing the number of acorns available to produce seedlings and feed wildlife.

~Lester P. Gibson

No, this isn’t what you think…it really is a post about acorns (I need a break from the other nuttiness). It is a quick follow-up to my recent post on acorn weevils. I became fascinated with the goings-on inside acorns after seeing the weevil larva pull itself out of the nut and wanted to learn more.

acorns

It is a very good year for acorns (click photos to enlarge)

I collected 100 acorns and did the float test I mentioned in that first post (I used only white oak acorns for this test although the photo above shows both white and northern red oak acorns). An astonishing 45 out of 100 acorns were floaters, indicating they were “unsound”, which means they possibly had acorn weevil larvae or some other insect inside. I separated those out and placed them in a plastic tub and have been collecting the larvae that emerge. In the last week, 13 insect larvae were found crawling around in the tub. Most were the large chubby weevil grubs I found before, but a few were different.

Acorn insect larvae

Acorn insect larvae

The photo above shows samples of the three types of larvae that have emerged…the large weevil grub on the right; a much smaller weevil grub in the middle; and a moth larva on the left.

Acorn weevil larvae big and little

Acorn weevil larvae – big and little

A few of the grubs were small versions of the chubby acorn weevil larvae. These may be from a different species of weevil rather than simply smaller versions of the dominant larvae I have seen. Online resources state there is another acorn weevil with a short (less than half its body length) rostrum that lays its eggs in acorns that are on the ground (the species I showed in the last post, with the long rostrum, lays eggs in developing acorns on the tree). And it appears there may be more than one species of weevil that lays eggs in developing acorns, so the small larva shown in the middle above could certainly be that of a different species.

Acorn moth larva and acorn weevil larva

Acorn moth larva (left) and acorn weevil larva (right)

There was also one caterpillar that crawled out of an acorn this week. From what I can decipher from scattered references, there may be a couple of species of small moths that lay eggs in acorns. The information I found suggests they lay eggs into existing cracks or openings in acorns (including the exit holes of acorn weevil larvae), although one reference also stated at least one species of moth caterpillar can chew through the shell of an acorn.

Acorn moth larva

Acorn moth larva

The moth caterpillars are easily distinguished from the weevil larvae by their more elongate shape, and the presence of three pair of legs just behind the head capsule (the weevil larvae lack legs). I placed several of the insect larvae in small containers with potting soil and hope to rear them to see what emerges next spring (or whenever since some may take more than one year). The literature indicates a wide range in the percent of any years’ acorn crop that is infected with insect larvae, depending on location and oak species. The study cited in the opening quote found an average of 52% of the northern red oak acorns at a site in Ohio were damaged by insects of various sorts. My very limited “study” indicates 45% are unsound.

Hickory nuts with weevil exit hole

Hickory nuts with exit holes

And it’s not just in acorns. It is also a good year for the hickory nuts in our woods, and, much to my surprise, I am finding a small percentage that have very neat exit holes in them. These nuts have much harder and thicker shells than acorns, so it will be interesting to see what is making them (I am assuming a weevil larva of some sort). Seems like there are some pretty amazing things going on out there in the forest.

 

 

Ground Squirrels in Trees

There was no variation in his manner of proceeding all the time I observed him. He was alert, cautious, and exceedingly methodical.

~John Burroughs, on observing a chipmunk, 1894

On our recent mountain trip, we camped at Hickory Ridge Campground at Grayson Highlands State Park.  In addition to several maple, birch and (appropriately) hickory trees, there were a lot of northern red oaks.

forest and boulders behind campsite

The forest provided a good mast year and plenty of places to feed and hide (click photos to enlarge)

Like back home, it appears to be a good mast (the nuts of forest trees) year at the park. And that means lots of activity by the forest dwellers to gather, eat, and store these nuts. We saw several gray squirrels working in the trees and underneath, but, the dominant forest floor activity, by far, was the busy to-and-fro movements of Eastern chipmunks, Tamias striatus. Both mornings in camp, while sipping our morning coffee and tea, we enjoyed watching them going about their busy lives.  They had definite paths from one tree trunk to another, often ending atop a boulder where they were feeding. But, the second morning, I saw one do something you don’t think of a ground squirrel doing…

chipmunk on shelf fungus

This chipmunk was a real tree climber

…climb a tree. I remember the first time I saw that years ago was when one of my dogs startled a chipmunk out in the yard. The little chippie ran straight up a tree trunk to a height of about 20 feet, then turned and scolded us both. Turns out, many Eastern chipmunks are regular tree climbers, either to escape danger or to collect nuts like acorns and hickory nuts.

chipmunk on shelf fungus eating

Eastern chipmunk eating something on its shelf fungus perch

This particular chipmunk had a routine that took it from foraging on the ground under some scattered trees, up the back side of a black locust tree near our campsite, and then out to a shelf fungus projecting off the tree just beneath a fork in the trunk. The first time I saw it, the fungus was in the shade, and the chippie dropped down onto the ground right as the rising sun was about to illuminate its perch. But, being creatures of habit, it soon returned and proceeded to feed on some small morsel it had scavenged on the ground.

chipmunk on tree branch

This chippie had two trees it liked to climb

On its next trip to the ground, it scurried through the leaf litter about 75 feet and climbed a different tree and soon perched in a prominent spot atop a broken limb.

chipmunk on tree branch 1

Always on the alert for danger

This tree had a large cavity in deep shade near this broken limb, and the chipmunk visited that area a couple of times as if storing some food from its cheek pouches. But it would always pause on the broken limb and look around for potential danger (and to see where that guy with the camera had moved to).

chipmunk with acorn

Chipmunk with acorn

chipmunk chewing an acorn

Chowing down on an acorn

After one foraging foray, the chipmunk returned to its perch with an acorn. Naturalists have observed that Eastern chipmunks are capable of carrying as many as 6 acorns at once in their cheek pouches and mouth, but this little guy seemed content with just one at at time. After chewing on it for a minute or so, the acorn fell to the ground. I’m not sure whether the drop was by choice or by accident, but the chipmunk didn’t run off to retrieve it. Instead, it began what some say is its second favorite activity…

chipmunk grooming

When not foraging or on alert, chipmunks are often grooming

…a bout of grooming. This chipmunk did a lot of grooming on both of its tree perches, but the motion is so fast that my image was usually blurred in the low morning light. After taking way too many photos of our cute little friend, I finally had to put away the camera and finish packing up the gear. All the while, the little striped ground squirrel kept up its busy pace of feeding, grooming, and looking for danger. Indeed, as Thoreau observed one autumn (in 1858) at Walden Pond, What a busy and important season to the striped squirrel! [He] is already laying up his winter store.

Post script – Ironically, as I finished writing this, I heard both a gray squirrel and a chipmunk giving alarm notes out back. I went outside expecting to see either a hawk, snake, or cat, but found no sign of a predator still around. The low-pitched clucking note of chipmunks is a woodland sound that fooled me years ago when I first heard it, thinking it was some sort of bird. Listen here for the various chipmunk alarm calls. The note I just heard occurs after the high-pitched chipping alarm on this audio file. Research shows a tendency for the high-pitched notes to be given when a terrestrial predator is spotted, and the low-pitched notes when an aerial predator is nearby.

Transformation

In all works on Natural History, we constantly find details of the marvelous adaptation of animals to their food, their habits, and the localities in which they are found.

~Alfred Russel Wallace, 1853

It is that time of year again…yep, the museum’s annual BugFest event is tomorrow, Saturday, September 17. Join us for an incredible array of exhibits and experts on all sorts of topics relating to the incredible world of insects and other invertebrates. I will be at the caterpillar tent again (where else?) this year out on Jones Street. Drop by for a visit (and if you have found a large caterpillar like a hickory-horned devil or an imperial moth larva, bring it!!). To celebrate another year, here is a series of photos from the yard, showing the transformation of just one of the stars of the show this year, and one of my favorites, the spicebush swallowtail.

Spicebush swallowtail in curled leaf early instar

Early instar spicebush swallowtail larva in curled leaf retreat (click photos to enlarge)

Female spicebush swallowtail butterflies lay eggs on the leaves spicebush or sassafras. The larvae spread silk across a leaf, causing the leaf to curl as the silk dries and contracts. This provides a retreat for the developing larvae (they move to a larger retreat as they grow).

Young spicebush swallowtail

Early instar larvae are considered bird poop mimics

The early stages are bird poop mimics (as are the larvae of many swallowtail species). But, they also have another strategy to avoid being eaten…

Spicebush swallowtail early instar larva head shot

Their fake eyespots are quite realistic

Large fake eyes make them look like small snakes, something some birds might think twice about trying to consume. They even have small white marks on the eyespots that make them look like moist eyes.

Spicebush Swallowtail larva feeding on Spicebush leaf

Later stages are green

As they molt, they turn green and the eyespots enlarge. All stages of the larvae also have a forked gland, the osmeterium, that exudes a foul-smelling compound that deters predators.

Spicebush swallowtail prepup

They change color once more as they prepare to pupate

About a day before they transform in preparation to pupate, the larvae change to an orange color, and start crawling. When they find a suitable site, they form what is called a prepupa, and attach themselves with a silk button at their base, and a silk loop near the head (they create a loop and then slide their head under it, looking somewhat like a telephone line repairman hanging on a pole).

Spicebush swallowtail chrysalis

The chrysalis resembles a piece of a twig

The next day, they molt their caterpillar skin one more time to reveal the chrysalis, which resembles a broken twig or piece of dried leaf. The ruse continues. This guy was photographed this morning and will remain in this state until sometime next spring, overwintering as a pupa (as do most of our common species of butterflies and moths).

Spicebush swallowtail adult

The end result – a spicebush swallowtail butterfly

Leading a Double Life on the Edge

There is more both of beauty and of raison d’etre in the works of nature- than in those of art.

~Aristotle (384 BC-322 BC)

The adaptations of insects in our yard are both beautiful and incredible. Here is a little more on some leaf edge caterpillars discovered the past few days…

Double-toothed prominent

Double-toothed prominent on elm leaf (click photos to enlarge)

One of the most exciting finds was a group of double-toothed prominent caterpillars (Nerice bidentata) on an elm sapling. These guys are amazing in that they have noticeable fleshy “teeth” on their dorsum that mimic the double serrated leaf edge of elm leaves, their host plant.

Double-toothed prominent early instar 1

Early instar of double-toothed prominent larva

Several of them molted over the past few days and I noticed what seems like a slight change in behavior between the different sizes. The smaller larvae are somewhat darker in color and seem to feed along the leaf edges in a more exposed position.

Double-toothed prominent on small leaf

Their color and pattern aids in the deception

The brown tips of the prolegs match brown spots along the mid-vein of the leaf.

Double-toothed prominent close up

Later instar

Larger larvae appear lighter in color, and seem to feed at an angle that puts them slightly under the leaf. The leaf underside is lighter in color than the top, so maybe this is why. The larvae also have angled stripes along their sides which mimic the venation of the leaves, adding to their effective disguise.

Double-lined prominent

Double-lined prominent on elm leaf

While looking at other elm saplings, I came across another species that seems to mimic both the leaf edge and the twigs of its host plant. When viewing the dorsal surface of a double-lined prominent (Lochmaeus bileneata), the reddish-brown color resembles an elm twig.

Double-lined prominent 1

The light stripes may mimic the leaf petiole

When viewed from the side, the white and yellow stripes along the cater[pillar’s body look like the mid-vein of a leaf, and the brown resembles dying leaf tissue.

Double-lined prominent 2

Even the head stripe helps in the disguise

The feeding position (head towards the tip of the leaf, body along the mid-vein) reinforces the effectiveness of the cryptic pattern and colors, with even the stripes on the head capsule resembling part of the angled leaf venation. I suppose it should come as no surprise that I can spend hours wandering around the yard, amazed by the small wonders all around me. I hope you all can spend some time outside this holiday weekend and discover wonders of your own.

Life on the Edge

In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.

~Charles Darwin

Unicorn caterpillar wide view

Unicorn caterpillar positioning itself in a portion of the leaf it has eaten (click photos to enlarge)

I shared some images last week of one of my favorite moth larvae, the unicorn caterpillar. Their shape, coloration, and behavior allow them to blend in remarkably well with their environment. Turns out, they are not alone in their ability to hide in plain sight along the edges of leaves. It is a common strategy of many caterpillars, and I was delighted to find a few other species of leaf edge mimics in the yard over the past few days.

Wavy-lined heterocampa wide view

Wavy-lined heterocampa on hophornbeam leaf

One of the more remarkable leaf edge look-alikes is the wavy-lined heterocampa, Heterocampa biundata. It is variable in color, but frequently has brick red and white splotches along its sides that resemble necrotic leaf tissue. I assume this is a particularly effective camouflage for species that live during late summer and early autumn when many leaves are pock-marked by such splotches.

Wavy-lined heterocampa

Blending in to a hickory leaflet

This species is a generalist feeder on a variety of woody plants (I found them on two species of trees here in the yard). In addition to the leaf splotch patterns on their sides, they tend to align themselves along leaf edges in the areas of leaf they have devoured. The slight bump along their dorsal surface outline helps with this camouflage by making them look more like a leaf edge contour.

Chestnut Schizura on Viburnum nudum side view 1

It requires a careful look to pick these leaf edge mimics out of the background of green

Another excellent leaf mimic is the chestnut schizura, Schizura badia. I found a few feeding on the leaves of a possumhaw, Viburnum nudum. They tend to place themselves inside the outline of portions of a leaf they have consumed, once again making for a well-camouflaged caterpillar.

Chestnut Schizura on Viburnum nudum side view

A closer look

They also have brownish splotches that mimic dying leaf tissue.

Chestnut Schizura on Viburnum nudum

Dorsal view

This species is characterized by a diffuse yellow saddle over the dorsum of the abdomen and a large, irregular-shaped, brown patch on the sides.

Chestnut Schizura on viburnum leaf

A close relative of the unicorn caterpillar

It is a close relative of the unicorn caterpillar and also has the ability to shoot a blend of acids at would-be predators. The defensive spray comes from a thoracic neck gland and can be shot a distance of up to several inches.

Small-eyed sphinx caterpillar on cherry wide view

Small-eyed sphinx larva

Although not a leaf edge mimic per se, the other species I found yesterday does a good job of looking like a common leaf pattern on its host, wild cherry. I am pretty sure this is the first of its kind I have found in my years of caterpillar hunting. It is a small-eyed sphinx, Paonias myops.

Small-eyed sphinx caterpillar on cherry

The red splotches mimic leaf spots on wild cherry

The red splotches certainly are excellent mimics of the pattern on the underside of many wild cherry leaves this time of year. The behavior of this species helps with this deception  as it tends to stay underneath leaves (where the leaf splotches are most noticeable) during the day and then comes out to feed mostly at night. Wagner, in his excellent reference, Caterpillars of Eastern North America, wonders if the spots are more apt to occur on individuals feeding in the autumn, when cherry leaves tend to have more splotches. I continue to be amazed at the intricacies of nature found just outside our door. More on some other leaf edge larvae in my next post.