In early summer Pittsburgh birders tire of searching among dense leaves so we travel to Clarion County’s recovered strip mines for grassland birds. Yesterday five of us drove 90 minutes to look for open country birds we’ve found there in the past.
Dickcissels (Spiza americana) are back again this year and easy to find singing on the wires at Concord Church Road. These rare nomads were a Life Bird for me in 2012. Read this vintage article, Dickcissels, for the reason why they to come to western Pennsylvania.
Feathers wear out so birds molt to replace them. Most species molt their flight feathers one pair at a time, losing a matching feather on each side, so they can continue to fly. Not so with swans, geese and whistling ducks. They replace all their feathers shortly after the breeding season in a single annual synchronous molt. During the molt they cannot fly.
Though it seems crazy to lose the ability to fly these large heavy birds are safe on water and unsafe in flight if missing a few feathers. It works for them to lose these flight feathers all at once.
Geese rarely display their stubby wings but you can tell when they’re molting by looking at their tails. Most of the year their flight feathers cover their rumps (left). When molting (right) you can see a white rump patch.
Right now in Pittsburgh Canada geese are in their flightless period that lasts six weeks from mid-June to August. You’ll see them flock in or near large bodies of water, feeding on land and walking to the water to swim to safety. You might even notice they are not at grassy feeding places, such as Flagstaff Hill, which don’t have bodies of water nearby. Such sites are unsafe when they cannot fly.
Have you seen any Canada geese flying lately? No. Because they can’t.
Whenever we see this sandpiper species he’s up to his ankles(*) in water and is poking with his long bill to eat insects, crustaceans, mollusks and amphibians.
Solitary sandpipers (Tringa solitaria) are distinguished from other shorebirds by a white eye ring, white spots on dark back, and the fact that they’re usually alone. We see them on migration as they travel between their wintering grounds in Central and South America and breeding grounds in the muskeg bogs and boreal forests of Canada and Alaska.
Everywhere they go they land on the ground and walk in water. I have never seen one in a tree and yet …
When solitary sandpipers reach their breeding grounds they nest in trees.
Solitary Sandpipers use old nests of songbirds in trees, especially those of American Robins, Rusty Blackbirds, Canada Jays, and Cedar Waxwings, which are usually near the trunks of small trees a few yards above the ground, but may be higher. [that’s 9 ft or higher]
Males identify old songbird nests that have potential, and females apparently make the final selection. Females modify the nest by removing old lining and often relining with fresh materials.
One of the joys of early spring is finding the first Louisiana waterthrush (Parkesia motacilla) of the year as it forages along a stream and sings its loud distinctive song. The bird is so loud that we hear him first then look for movement along the water’s edge. He stands out because he constantly bobs his tail. In fact he bobs the entire back end of his body!
Just half a minute of this video illustrates what I mean.
A few weeks later the spotted sandpiper (Actitis macularius) arrives to walk the water’s edge bobbing the entire back end of his body, too.
Same habitat, same movement. Is there some advantage in drawing attention to one’s back end? Why do these birds wag their tails? I found a partial answer at All About Birds:
… waterthrushes don’t actually wag the tail, they dip (or teeter) the entire rear of the body by moving their ankle joints. This motion is very much like the bobbing of Solitary and Spotted Sandpipers, which share their wetland habitats. It’s been suggested that this habit might either help them avoid scaring off their prey or possibly startle their prey into motion.
There’s plenty of time to watch them teeter in the weeks ahead. My first Louisiana waterthrush of 2021 was at Cedar Creek Park in Westmoreland County on 30 March. I expect the first spotted sandpiper next week.
Bonus! Here’s a closeup of a Louisiana waterthrush singing:
(photos from Wikimedia Commons; click on the caption to see the originals)
p.s. Others birds pump their tails including eastern phoebes, palm warblers, hermit thrushes, wagtails and pipits. It is not quite the same motion.
When Europeans explored the Pacific they sometimes named islands for the day they found them. Thus Easter Island (Rapa Nui) was named by Dutch explorer Jacob Roggeveen who encountered it on Easter Day 5 April 1722 and Christmas Island (Kiritimati) was given its English name by Captain James Cook on Christmas Eve 1777.
Maxwel Hohn spent four years filming a tiny migration we never see. Every morning western toad tadpoles (Anaxyrus boreas) swim from their nighttime shelters to feeding areas in the lake, then back again to hide at night. The result is his award-winning 8+ minute video: Tadpoles: The Big Little Migration.
Our eastern American toads (Anaxyrus americanus) are closely related to western toads so I wonder if they do this, too.
Meanwhile, if the video wasn’t amazing enough for you, here are two more amazing things about tadpoles and toads:
Don’t worry that our tadpoles won’t survive the freezing temperatures this morning in eastern North America. Even if the ponds freeze, tadpoles are able to overwinter under ice. See photos at What’s Under the Ice? Wow! Winter Tadpoles from Oakland Twp, Michigan.
Do you know where North America’s toads came from? South America. And they didn’t walk! “Based on DNA sequence comparisons, Anaxyrus americanus and other North American species of Anaxyrus are thought to be descended from an invasion of toads from South America prior to the formation of the Isthmus of Panama land bridge, presumably by means of rafting. — from the Wikipedia description of the American toad.
Native from Florida to Argentina, the snail kite (Rostrhamus sociabilis) is a gregarious bird of prey that eats only one thing: freshwater snails in the genus Pomacea. Its beak is specially shaped to do so.
The Snail Kite’s slender, deeply hooked, sharp-tipped upper mandible permits it to cut the columellar muscle of Pomacea snails and remove soft tissues from the shells. The arc of the upper mandible approximates the inner spiral of the snail’s shell.
In the old days before humans took over Florida’s landscape, snail kites ranged over half the state, but we drained and diverted more than 50% of Florida’s wetlands, the snail kite population crashed and was listed as Endangered in 1967. Twenty years ago, from 2000-2007, their population dipped so low that scientists feared they would go extinct in the U.S. Then a curious thing happened. Their food supply changed and the kites changed so they could eat it.
Before this century the snail kite’s main food was the native Florida apple snail (Pomacea paludosa) but an invasive species, the island apple snail (Pomacea maculata), arrived in 2000 and began to spread in Florida’s lakes and water management areas.
When the island apple snail first arrived in Florida the snail kite population dropped but less than a decade later the population began increasing. Did the birds initially have a tool problem? Were their beaks too short to get at the snail inside the larger shell? A recent study from the University of Florida indicates this was probably the case. Since 2007…
Researchers found that the birds with bigger bills were surviving, and their offspring were inheriting the bigger bills. …
“We found that beak size had a large amount of genetic variance and that more variance happened post-invasion of the island apple snail. This indicates that genetic variations may spur rapid evolution under environmental change,” Fletcher said.
Goose barnacles often attach themselves to old wood and float from tropical seas to northern shores including the shores of Britain. The barnacles pictured here and in the video below are Lepas anatifera. Their bodies are supported by a long, flexible stalk (a peduncle) that resembles a goose neck.
These fascinating crustaceans are goose barnacles. They live in unmistakably dense colonies, often attaching themselves to marine objects. They occasionally get washed up around our shores. ??
Nowadays that story sounds silly but we shouldn’t be too smug. We still create stories to explain things we don’t understand and spread them quickly on the Internet. In the future our fantastical stories will sound silly, too. I can think of a few about the coronavirus.
(photos from Wikimedia Commons; click on the captions to see the originals)