Birds learn how to fly, never knowing where the flight will take them.
This is a brief update on the recent posts where I shared a few sightings of tagged birds – one, a Common Raven in Yellowstone, and three American Oystercatchers on Masonboro Island in southeastern North Carolina. First, the shorebirds at Masonboro. When I got home, I searched the web for information on banded American Oystercatchers and immediately came up with the American Oystercatcher Working Group. This is a conservation group of scientists and resource managers created in 2001 to monitor oystercatcher population dynamics and promote the conservation of American Oystercatchers and their habitats. Their web site has information on reporting sightings of banded birds so I submitted my data. Once they verify your observations and the leg band ID, you receive information on the birds you reported.
Here are the three birds and what we know of their stories…
CUU was captured and banded on 4/26/16 on Masonboro Island. There have been 33 reported sightings since that time. There are 3 confirmed breeding/nesting seasons on Masonboro (the nest was found); In other years, the bird was seen on Masonboro during the nesting season, but a nest was not observed. Winter sightings were at Dewees Island, near Charleston, SC, in December of 2017 and 2018, a distance of approximately 140 miles from Masonboro.
This is the homebody of the three birds, never having been reported more than 18 miles from Masonboro (on Bald Head Island), even in winter. Captured and banded on 4/26/16 on Masonboro. Reported sightings 43 times. Also has 3 confirmed nests on Masonboro Island and has appeared in that location during the other breeding seasons, but no nest was observed.
The long distance traveler of the group. Captured and banded on 4/26/16 on Masonboro Island. Re-sighted 56 times. Five confirmed nesting seasons on Masonboro (nest found). Observed in Cedar Key, Florida, every winter since it was banded. That is a distance of about 460 miles one way every year.
The map below shows the apparently consistent winter travels of the three American Oystercatchers.
The type of leg band that the oystercatchers had can be viewed and reported from a distance using binoculars, a scope, or a telephoto lens. That type of information gives a data point for any time someone reports seeing the bird. The “tag” on the ravens in the Yellowstone research project includes color coded leg bands for visual observation and a solar-powered GPS backpack with an antenna that submits the birds’ locations every 30 minutes throughout the day. This combination gives a much more detailed view of the birds’ behavior.
The 70 or so tagged ravens are a part of a study looking at interactions of these intelligent birds with their habitat (foraging and roosting sites for example) and with large carnivores (bears, mountain lions, and wolves). In an earlier post, I mentioned I had found out about this research online and had contacted the lead scientist, Dr. John Marzluff. He identified this bird as the female at Tower Junction (the location where she was captured and tagged) with transmitter 7493-2. She was captured on December 10, 2021 and we observed her on 1/20/22 at Tower Junction, patrolling the parking lot at the pit stop and recycle bins.
Her data is now visible on the Animal Tracker app (for iPhone and iPad – search for raven and then scroll down to Tower_Junction_female). She tends to move mostly between Tower Junction and Lamar Valley, a distance of about 12 miles. Her longest flight to date has been to an area north of the park entrance along Hwy 89, a distance of about 22 miles. Some of the tagged ravens have dispersed much farther, with one heading up to the Bozeman area, and another, the record-holder, flying up to Alberta, Canada.
Is she going to carcasses in Lamar or just stopping at places where there are concentrations of visitors? I would love to be out there and recording data on these birds to see what they are actually doing. It is a treat to get a peek into the private lives of wildlife. But, more importantly, this is valuable information that may help researchers and resource managers make better decisions for protecting these birds and their important habitats.
The edge of the sea is a strange and beautiful place.
Last week was another first for me – a canoe camping trip to Masonboro Island. Masonboro Island is one 10 sites that make up the NC Coastal Reserve and National Estuarine Research Reserve. This 8.4 mile long island reserve was protected in 1991 and is the largest undeveloped barrier island along our southern coast. It lies between Wrightsville Beach to the north and Carolina Beach to the south. We put in at Trails End Park along the Intracoastal Waterway. We had tried calling the Reserve office on the way down just to ask a few questions about access, but staff were not available. We planned to launch on an incoming tide (a necessity for easy access to some parts of the island) late in the afternoon. As we were loading the canoe, a vehicle and trailer with state tags pulled in and it turned out to be the staff person we had tried to call earlier (some days you get lucky). They had been out cleaning up some trash on one of the dredge spoil islands that comprise the reserve. She gave us a 10-minute overview of where to go and what to expect and we were off. There was a stiff northwest breeze, so the usual 20+ minute paddle took us about 45 minutes. We started looking for a camping spot that would provide a little protection from the wind and settled on an old over-wash area behind a small patch of maritime shrub thicket.
The wind continued to blow on our second day, finally dropping down late in the afternoon. I was a bit surprised by the lack of bird activity with just a few pelican fly-bys and only a handful of shorebirds in sight during the day. The most abundant was the ubiquitous Sanderling, the energizer bunny, wind-up toy of birds that can be found on any sandy beach. I always enjoy watching them chase back and forth in front of the wave action, gleaning whatever tiny food morsels they can find along the beach. I spent a lot of time just watching their antics and trying to get photos of their high enery movements. They were more cooperative than the other species of shorebirds we saw in terms of tolerating our presence, especially if you just got out ahead of them as they moved down the beach and sat still. They would forage until they got just even with me and quickly run a few feet just beyond me to resume feeding.
Sanderlings can be found any month of the year on our beaches, but the largest numbers occur during migration in spring and fall. They breed in the high Arctic tundra. Their migration routes and distances vary considerably with the average migration distance from wintering to breeding grounds being over 5000 miles. No wonder they are so busy running up and down the beach feeding!
At low tide we went back to the sound side of the island and saw why everyone says you need to paddle over on an incoming tide. The large bay we paddled in on was now a giant mud flat. Eastern Mud Snails (Ilyanassa obsoleta) covered the mud. It is hard to imagine how many snails are out there when you look out and see black dots covering the entire mud flat. They feed primarily on microorganisms (e.g., bacteria, blue-green algae and diatoms) that grow in and on the surface of the sediment but will also scavenge any dead fish or other animal carcasses. They are native to the Atlantic Coast of North America but have been accidentally introduced to the West Coast where it is considered an invasive species that is out-competing some of their native snail fauna.
The other notable thing you see at low tide are the oyster reefs along the marsh edges. Eastern Oysters are able to survive being exposed by tightly shutting their shells and maintaining water inside during the low tide cycle. These are incredibly important salt marsh organisms due to their water filtering capabilities (one oyster can filter up to 50 gallons of water a day while feeding), shore stabilization properties, and the habitat provided by the structure of oyster reefs. And they are a favorite food of many creatures from crabs to shorebirds to us humans. I also learned a valuable lesson about their habitat. We walked out in our rubber boots to examine some oysters. I stood in one spot for a few minutes and when I started to turn to walk away, one boot remained solidly stuck in the mud while the rest of me did a sideways plop into the thick goo (luckily, no photos exist of this embarrassing moment in the life of a naturalist).
Later in the day, the wind finally started to subside and we decided (well, really, Melissa decided) to move our campsite closer to the ocean in a small break in the dunes. The high tide mark was about 15 feet from our tent, so I kept an eye on the incoming ocean water. But, all was good and it turned out to be one of the most beautiful campsites ever.
We spent the afternoon walking up and down the deserted beach (we were the only humans on the island for our entire stay) looking for shells, birds, and scanning the ocean for marine life (we did finally see a pod of dolphins).
The most interesting birds we observed were several pairs of American Oystercatchers scattered along the beach. We heard many have just recently arrived back here for breeding (they typically nest on sand and shell beaches, at marsh edges, and other areas with little or no vegetation). Oystercatchers are boldly patterned and large for a shorebird and they have a conspicuous long red bill. They use this bill to probe for mussels and other invertebrates in sand and mud and to feed in a remarkable way on oysters and other shelled creatures. As the tide drops, oystercatchers move out onto the oyster reefs and search for oysters with partially open shells. They then use that knife-like bill to stab the abductor muscles that hold the two halves of the shell together so the oyster cannot close. The bird then pulls out and eats the soft parts of the oyster. They also use their beak to hammer open softer shelled bivalves.
While watching these fascinating birds, I noticed some leg bands on one bird in three of the pairs I observed. Back home, I searched the internet and found the banding program is run by the American Oystercatcher Working Group. From their web site – Since 1999, over 6,000 American Oystercatchers have been banded in the U.S. and Mexico. Banding individual birds helps researchers learn about demographics, movement, habitat requirements. American Oystercatchers are a species of concern due to declining numbers in recent decades. I filled out the report forms and should soon be notified of the data on these particular birds. I’ll be sure to share when I get additional feedback.
The wind died and we enjoyed another beautiful sunset, dinner, and the a campfire on the beach (something Melissa has always wanted). She found some abandoned firewood near our first campsite (you must bring your own firewood if you want a campfire on Masonboro). We built a fire below the high tide mark so the next tide would remove all traces and we enjoyed a long and relaxing campfire with the sounds of the ocean and a beautiful night sky as our only companions on our last night on this magical island.
The staff person we spoke with at the launch site mentioned that coyotes are on Masonboro and we should protect our food (just as we would from any other critter when camping). We stored our supplies in our “bear canister” and, though I kept a lookout at sunrise and sunset, I never saw any mammals on the island. But on our last morning, we walked down the beach and found a line of coyote tracks that went by our campsite. Some time during the night, the coyote had come down off a steep dune face and trotted in the typical straight line gait until it got to within about 50 feet of the dune break where our tent was set up. It then veered off toward the ocean and returned back to above the high tide mark once it was about 50 feet past us. This is why I like our trail cameras back home so much – you never know what is going on outside after you go to sleep.
Being by ourselves on a deserted island is a good way to purge some of the world’s troubles from your brain for at least a short while. Masoboro looks like it could be a bit crowded at times in warm weather, but we lucked out and experienced the island solitude for a couple of days and it was good!
One thing we did to pass the time was walk along the beach, looking at the small wonders that wash up from the depths. We collected a couple of shells but I really enjoy looking at the patterns created by the forces of wind and water. Below are a few shots of natural patterns we found as we enjoyed the island and nearby beaches.