They Are Catching More Than Just Gnats

may my heart always be open to little birds who are the secrets of living

~ee cummings

Here is a long overdue update on those little birds that nested just outside the garden driveway gate at the Botanical Garden…I am happy to report these diligent parents were apparently successful in rearing their young. You may remember my earlier post where a pair of blue-gray gnatcatchers were building the nest (they finished it around April 10). A few days after that post, I saw the female incubating the eggs, so I tried to keep an eye on her to see when they might start feeding the young. Finally, I saw her off the nest the first week of May. I wasn’t able to get out to photograph them until May 7. That was probably about 6 or 7 days after they hatched. I had trouble counting the tiny heads even after looking at my images from that first feeding day, but I could tell there were at least three young. Later, I saw the fourth beak pressing skyward on one of the feeding bouts, so the total was four.

BG gnatcatchers both adults at nest

Both parents arriving at nest together (click photos to enlarge)

The feeding bouts were fast and furious, with adults staying just a couple of seconds on each trip. What amazed me on that first day was the large number of huge craneflies that the parent birds were bringing in.

cranefly brought to nest

A large adult cranefly is jammed down an open mouth of one of the nestlings

close up of cranefly going to nestling

That a lot of wings and legs to swallow for such a tiny bird

BG Gnatcatcher at nest

Nestlings sometimes had to wait a bit before they could get anything else down

It seemed like about half of the food items brought on that first evening were craneflies. There is a nearby creek and large vernal pool that may be the source of so many of these huge flies (their larvae are aquatic), but I was impressed how many the adult birds were able to catch. Even more impressive was how many the tiny nestlings were able to swallow. On many occasions, a parent brought another food item, but I could still see the long legs of the previous meal sticking out of the beak of one of the recently fed young.

BG gntcatcher with fecal sac

Female removing a fecal sac from a nestling

Of course, what comes in, must go out, so after every few feeding trips one of the young birds would raise its rear end after the adult had passed on a prey item, and the adult dutifully plucked the pre-packaged fecal sac and flew off. Data shows they usually drop it after flying 30 to 40 feet away from the nest (this helps keep the nest area clean of smelly poop that might attract predators).

nestling begging

Nestlings are getting more feathers on their head by May 11 (compare to earlier photo)

I spent some time photographing the feeding of young on three separate occasions, all after the Garden closed at 5 p.m. By the third date, May 11, the young were noticeably larger, more active in the nest between feeding bouts, and getting more feathered, especially on the head. Their huge gape and bright yellow mouth linings were hard to miss, and surely provide a great target for tired parent birds bringing in the food.

feeding the group

Hungry mouths begging for food

I was amazed that, after that first day of a menu heavy on craneflies, the last day I watched them, the adults brought in nary a one. Most of the food items were much smaller, and were difficult to identify even after zooming in on the images.

Adult brining a small moth

Bringing in what looks like a small moth

But the pace of feeding had quickened. That last day, May 11, I decided to keep track of the feedings. I stood out there for a total of 86 minutes that evening. During that time, the adult birds made a total of 51 feeding trips. The longest interval between feedings was 6 minutes. On several occasions, there were 2 or 3 feedings within the span of a minute!

feeding from above

The last day, a new feeding perch was used…the hang-down-from-the-branch-above technique

Although I was hoping for another day of shooting the nest, I thought they might fledge before I returned, as I was taking a long weekend. Sure enough, when I returned to work on May 16, the nest was empty. Records show the young usually leave the nest 10-15 days after hatching, so that puts these guys right on schedule. Here’s hoping they all made it and are out there learning to be on their own.

Catching Gnats and Plucking Lichens

More than with most species of small birds, the attention and interest of the observer center about the nesting habits of the blue-gray gnatcatcher because of the great beauty of its nest.

~Francis Marion Weston, 1949

One of my favorite spring arrivals is the plucky little blue-gray gnatcatcher. It is tiny, but bold. It looks a bit like a tiny mockingbird, but builds a nest like a large hummingbird. My friend, Mary, found a nest at the Garden recently and emailed me where to look as I prepared for a program. I never did find that one (they are often very well camouflaged on a branch). But, a week later, as I was leaving work, I heard the familiar “Steeve” call, looked up, and saw one fly into a small tree. I got out my binoculars, and was pleased to see a nest in progress.

Blue-gray gnatcatcher nest empty

Blue-gray gnatcatcher nest (click photos to enlarge)

A few evenings later, I brought my camera and spent some time watching this industrious duo go about the business of finishing what is certainly one of nature’s most beautiful nests. By this time, it looked like the nest was nearing completion, but the gathering of materials, and fine-tune adjustments, continued for over an hour as I watched.

Blue-gray gnatcatcher with spider silk on bill

Female bringing in spider silk

The nest is a deep (about 3 inches) cup about 1.5-2 times the size of a ruby-throated hummingbird nest. Otherwise, they look almost identical – a somewhat high-walled, elastic nest covered on the outside with lichens and held together with spider silk. The inside is lined with soft materials like plant down, hair, and fine feathers.

Blue-gray gnatcatcher in nest 2

Male checking the feel of the nest

As I watched, both adults were busy contributing to the efforts. During the breeding season, the male blue-gray gnatcatcher (photo above) can be distinguished from the female (photo below) by the presence of their black forehead and supercilium (a stripe that runs from the base of the birds beak and above its eye). The female’s head is plain gray.

Blue-gray gnatcatcher in nest 3

Female inspecting the progress

I had my big telephoto plus a teleconverter, so I was well away from the nest. The birds chose a very busy location for their activity, right next to a road and walkway that is popular with Garden visitors, so I don’t think they minded me watching them.

Blue-gray gnatcatcher in nest 5

Male placing a lichen

There were times when nothing happened at the nest for 10 minutes or so, then there were bursts of activity with a bird bringing in materials (especially pieces of foliose lichens – they look like lichen cornflakes) every minute or so. The usual routine was to fly into  a branch next to the nest, pause, then hop into the nest and place whatever material was brought in. Then there was often some fine-tuning, placing the lichen just so, inspecting it for a second, and then off again. Time spent in the nest on any one visit was usually less than 20 seconds. References say it takes about a week to complete a nest, but I think this pair could do it much faster based on what I saw.

Blue-gray gnatcatcher singing

Male singing

Blue-gray gnatcatcher preening

Male preening

In between nest-building activities, the pair would pause for some singing, preening, or the important duty of nest protection. I am a bit worried about this particular nest, since it seems in a more open location than many I have seen. There are a lot of hazards to any nesting bird, especially one so tiny. I witnessed a few bouts of territorial defense as this pair chased after a crow and a pair of blue jays that flew through their air space. And a pair of brown-headed cowbirds received a lot of attention when they perched within 50 feet of the nest. Both adults repeatedly dive-bombed the cowbirds, who seemed uninterested. They eventually flew off, and nest building resumed about 5 minutes later.

Blue-gray gnatcatcher pressing down in nest 1

Shaping the cup

The final stage of nest building is refining the shape of the cup. This is something they put their whole body into…the adult plops down into the nest with just their head and long tail (the tail accounts for about 45% of the total body length) visible and pushes against the sides of the nest, shaping it as they rotate their body around, flexing the sides until it is just right.

Blue-gray gnatcatcher pressing down in nest

Putting your whole body into getting the shape just right

At times, I could barely see their head at all, with just the slender bill projecting above the lichen wall. I checked on the nest the next few days and saw no activity, so I figured they had completed construction. And now, I see the female sitting in the nest for long periods of time, so I assume she is incubating her eggs. I will keep you posted on their progress.

Great Gray Addendum

I had heard about a Great Gray Owl nest in the park, so the morning after seeing the one up near the Beartooths (by the way, we did not find a nest at that one – yet) I decided to try to locate it. I knew roughly where it was as several photographers had mentioned it. After climbing through some dense dead-fall in the forest, I saw a few people with long lenses, and knew I was at the right spot. I was a bit concerned about people knowing the location of the nest due to disturbance, but I will give that group credit – they were very respectful and quiet and at a reasonable distance.

Great Gray Owl in nest 1

Great Gray Owl in nest (click to enlarge)

Great Gray Owls are our largest species and the huge facial disks give them an elegant, all-knowing countenance. The female is larger than the male and incubates the eggs. The male will hunt nearby and bring her and the chicks food. I sat with her for about an hour after the other group left, admiring this magnificent bird of the north, and felt privileged to be there. Finally, she turned in the nest with her tail feathers pointing my way, and I knew it was time to leave.

Wrens in the Yard

Caroilna Wren

Caroilna Wren in brush pile in the yard (click to enlarge)

While doing some chores yesterday (sweeping unbelievable amounts of accumulated pollen off the screen porch) I heard the resident Carolina Wrens scolding something. Since their new nest location is right off the screen porch I thought it might be me disturbing them, but it was so emphatic I decided to take a closer look. The nest this year is under the top of the propane tank, which sits off the screen porch.


Propane tank housing Carolina Wren nest

One wren was bringing a food morsel to the nest and was still scolding when I went out (that is a neat trick, your mouth full of bug and you still can screech and squawk at the top of your lungs). Now I am thinking snake. I looked around and didn’t see anything, but then noticed something move on the support column for the porch.

At first glance I thought it was a huge slug, but then realized it was the underside of a small loop of a snake’s body extending out from the other side of the support. I poked my head around and there was the cause of the wren’s concern – a young Black Racer. The snake was climbing down the support and quickly vanished into the pile of pipes and cinder-blocks stashed under the porch.

Carolina Wren nest

Carolina Wren nest (click to enlarge)

I looked inside the propane tank with my flashlight and all was well – I could see at least 4 baby wrens at the entrance to the nest. The sides of the tank may (I stress may) be too slick for the snake to climb on, or perhaps it just had not yet zeroed in on where the nest was located. At any rate, it will be interesting to see if the baby wrens make it another week or so until fledging after such a close call.

Caroilna Wren

Caroilna Wrens have attitude (click to enlarge)

Carolina Wrens are one of my favorite birds – always energetic; exuding perkiness with their inquisitive attitude, bounce in their step and their slightly cocked tail. They are monogamous, and maintain their pair bond and territory throughout the year. In spring, males may build several nests and the female chooses one to her liking. As many of you may well know, nests can be built almost anywhere there is a somewhat protected place or cavity a few feet off the ground. I have seen them in boots on a porch, under the hood of a truck, in a football helmet hanging in an open garage, and in a milk jug with the top cut out sitting inside a shed that had a gap under the door just large enough to allow a wren to squeeze through.

Carolina Wren nest

Carolina Wren nest (click to enlarge)

Nests are dome-shaped with an entrance on the side. They are made with a variety of materials including dried grass, leaves, sticks, pine needles, mosses, feathers, paper, and string. Most I have seen also have pieces of shed snake skin (or of plastic film or wrap that resembles snake skin). Scientists speculate that snake skin use in birds nests (several species of birds routinely add snake skins) is a deterrent to would-be egg predators, especially mammalian predators such as flying squirrels, that might become prey to snakes. Elizabeth Medlin and Tom Risch of Arkansas State University conducted a study using artificial nests in a cavity (simulating Great Crested Flycatcher nests) and quail eggs with snake skins in some nests and not others. The results supported the notion that snake skins deter the locally dominant mammalian nest predator, flying squirrels, from entering a bird nest and eating the eggs. None of the 40 nests with snake skins were attacked. Of the nests without, 20 percent had eggs eaten by flying squirrels.

Carolina Wren nest

Carolina Wren at nest container from previous year (click to enlarge)

I guess more study is needed to know if the plastic is as effective. I can’t quite tell from this photo whether that is real or faux snake skin in this nest. I am hoping this nest makes it, as it is always fun to see the wren family moving about the yard.