Flight Path

Birds learn how to fly, never knowing where the flight will take them.

~Mark Nepo

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…

American Oystercatcher with Band CUU (click photos to enlarge)

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.

Banded bird CUW

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.

Banded oystercatcher CUT

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.

Range map of the migrations of the three oystercatchers I observed

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.

Common Raven at Tower Junction showing the solar-powered GPS backpack and color-coded leg bands
The colored leg bands… Left – dark blue over gray, Right – light blue over metal

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.

The Tower Junction female raven tends to move mostly between that area (the dark cluster of data points is Tower Junction) and Lamar Valley (map from movebank.org web site).

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.

Lounging in the Lowcountry

I have heard it said that an inoculation to the sights and smells of the Carolina lowcountry is an almost irreversible antidote to the charms of other landscapes.

~Pat Conroy

I recently made a leisurely trip to the Lowcountry of South Carolina. Lowcountry generally refers to the lands along the coast from Charleston to the Georgia line, and is both a geographic and cultural designation. The impetus was to try to see the phenomenon known as strand feeding where dolphins run fish up on a muddy bank at low tide, coming up on the bank themselves as they grab the struggling fish. This behavior is primarily found in dolphins inhabiting the marshes south of Charleston.

Brown Pelicans in flight

Brown Pelican flyover on the boat trip through the marsh (click photos to enlarge)

After looking online, I booked a morning charter near Charleston with a boat captain that would take you out to look for dolphins. The day was beautiful with sunshine and a light breeze and the charter was timed with low tide to increase the chances of seeing strand feeding. Just after leaving the dock we began seeing a lot of bird activity. First, a pair of Brown Pelicans glided overhead, staring down at us.

Royal Tern in flight

Royal Tern in flight

Then a pair of Royal Terns zigged and zagged across the creek, one bird chasing another that had a fish, until the latter gulped it down. On the way out, our captain passed by a couple of fishing boats at a dock. One boat was a commercial shark-fishing boat, and as we passed by, that captain held up a Loggerhead Sea Turtle that he had just found inside the belly of an 8-foot Tiger Shark.

American Oystercatcher on marsh bank

American Oystercatcher on oyster reef

Cruising past the docks, the marsh creek narrowed, and we could see the plentiful oysters exposed by the low tide. And where there are oysters, there are American Oystercatchers. These large shorebirds have a unique feeding style. Their stout red bills are long, straight, an laterally flattened. The birds use them to pry or hammer open bivalve shells and to occasionally catch other small prey such as worms and crabs. Individual birds tend to differ in their feeding style with some being primarily “stabbers” (prying open shells), and others being mainly “hammerers” (breaking open shells by pounding on them). The back lighting on this bird highlighted some of the beauty of its unusual bill.

Morris' Lighthouse and pelicans g

Morris Island Light with Brown Pelicans in foreground

There were a few other people on the boat and we were all soon dropped off near Morris Island Light for some beach time. The lighthouse was once the primary safety beacon for Charleston Harbor.

Morris Island Light

Morris Island Light has been decommissioned and today stands far offshore

But the construction of long jetties to protect the main channel into the harbor in the late 1800’s greatly altered the sand transport patterns. In 1880, the lighthouse stood about 2700 feet inland. By 1938, it was at the water’s edge, and today, the lighthouse is on its own tiny island, roughly 1600 feet from shore.

Sand dollar

Sand Dollars and Hermit Crabs were common along the shore

The shoreline was sculpted by wave action and provided beachcombers with an array of shells and Sand Dollars. Finding an intact Sand Dollar is still one of life’s simple pleasures.

Laughing Gull

Laughing Gull in adult non-breeding plumage looks like it has something to say…

Laughing Gull bill agape

…but remained quiet.

A lone Laughing Gull was standing at the water’s edge and I noticed it gaping its bill every now and then. I sat down and watched and the gull would stand still for a minute, then turn its head and gape. I expected a sound, but nothing. The bird kept it up the entire time I watched. Gulls will often do gape displays when threatening other birds but it usually involves a head thrust and often a long call, so I still don’t know what this guy was up to.

Dolphin fin

Bottlenose Dolphin

Throughout the boat trip, we saw Bottlenose Dolphins swimming and feeding in the marsh creeks, but no strand feeding. One dolphin continued to come up close to our boat and the captain said it had been tagged for studies of their movements. It certainly was an odd-looking tag – a blob that appeared to somehow be attached to the back of the dorsal fin.

dolphin 1

Bottlenose Dolphin cruising next to the boat while we drifted

The dolphins were so close that we could hear them breathe each time they surfaced. The sky was bright blue, the temperature very comfortable, the birds and dolphins feeding throughout the marsh creeks – all in all, a great way to spend a morning in the Lowcountry.