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.
Yesterday afternoon I scanned the Cathedral of Learning with binoculars as I walked through Carnegie Mellon’s campus. Off in the distance I saw three juvenile peregrines playing in the sky.
The moment was perfect for a game of tag with brilliant sun and a strong gusty wind. I could see the three flipping and dipping in a game that builds important skills for hunting and courtship.
The photo at top, taken in Ohio by Chad+Chris Saladin, gives you a hint of what I saw from here.
So does this slideshow of Kim Steininger’s peregrine photos from Wilmington, Delaware, 2007.
Two juvenile peregrines play tag, 2008 (photos by Kim Steininger)
Yesterday I saw three of four juvenile Pitt peregrines plus one adult in a matter of minutes. I’m glad I was far enough away to see the whole event.
p.s. The four Pitt peregrines fledged in two groups over a period of one week. The first two fledged on 4 & 5 June, the third late in the day on 8 June, the fourth around 11 June. Because the first group flew so well by the time the second group fledged it was impossible to find all four at the same time. Fledging date of #4 is based on behavior and perching location. Some perches at Pitt are used only by newly fledged birds, then never used again.
Yesterday’s play session in the sky was 1 male and 2 females. Size was obvious.
I stopped by to see how the Goodyear burrowing owl was doing, and when I first pulled up it looked like nobody was home. All of a sudden he popped his head out of the burrow. I was dying! pic.twitter.com/OjeXm0tzCg
Brown-headed cowbirds (Molothrus ater) are the blackbird we love to hate.
Well known as a brood parasite, the female cowbird lays her eggs in the nests of smaller birds. The hosts foster her eggs and chicks while their own nestlings die. It’s particularly sad when we see a warbler feeding a cowbird chick knowing that his own nestlings did not survive.
I went snorkeling and came back an hour later. As I was getting out of the sea I saw the crow pull my trousers out of my bag which were rolled up. It pulled the trousers out and then went into the pocket and got my wallet out. I had my fins on, there was no way I could get to it. … The crow just looked at me with my wallet in its mouth and took it up to the top of the tree.
During the nesting season birds attack predators that threaten their young, driving them away from the nest before they get close. Peregrine falcons remember these threats all year long and are quick to harass raptors. Bald eagles are often their targets.
Even immature peregrines without a nest will harass raptors. This young peregrine drove five bald eagles off the ice in Cleveland one day last winter.
Pomarine jaegars (Stercorarius pomarinus) are ocean predators who steal the catch of other birds and prey on their young. A peregrine in Cleveland could not stand it when a jaegar ventured off Lake Erie to the Cuyahoga River in January 2015. See more photos at Peregrine vs. Pomarine.
Turkey vultures can’t catch a peregrine but will eat peregrine eggs if they get a chance. Below a male peregrine, Wade, drives off a turkey vulture. Go away!
I was working around 2.10 p.m. when I heard loud Peregrine alarm calls. I couldn’t see anything at the front, checked from my balcony at the back and spotted a Buzzard and seconds later a Peregrine dive bombing it! I went and grabbed my camera and caught a little bit of the action. This was Tom on his own, Azina was in the box with the chick the whole time. 5 May 2021 at 2.15 p.m. Fulham
When a peregrine sees a threat he doesn’t hesitate. “I’m warning you!”
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.