Bi John Pogacnik, Biologist
So far, spring has been a continuation of late winter with a steady roller coaster of temperatures. We see a nice day followed by a quick drop in temperature with a slow buildup until the next warm day. If you are able to get out on those rare sunny days with strong southwest winds, you are able to see some incredible migration.
We are still in early spring as migration goes and there can be high numbers of migrants on those good days, but the diversity is low. The early migration is usually made up with migrating blackbirds, robins, starlings and vultures. Insects are still in low numbers and during extended cold snaps they can be hard to come by. It is not a surprise that most of the birds currently migrating don’t need insects to survive. As temperatures increase and insects become more numerous, we’ll see an increase in insectivorous birds such as warblers, swallows, flycatchers and others. By looking at bird reports from southern Ohio, we can see that some of these birds may be heading this way.
On Thursday, I was at the Lake Erie Bluffs watching birds migrate. I started watching at 7:00 am and by 7:15, I saw a couple turkey vultures fly by. By the time I stopped at 10:00 am, I had counted more than 600 vultures. Vultures are supposed to use thermals when migrating and there were no thermals with the weather we had that morning. Thermals occur when the sun heats the earth’s surface causing air to rise. Migrating hawks and vultures use these thermals to gain altitude. They then glide downward in the direction they are migrating and look for the next thermal. This is an energy-efficient way for them to migrate. Missing on Thursday were the sun and thermals, yet the vultures still glided by.
Turkey vultures take advantage of another type of soaring called “contorted soaring.” They take advantage of what atmospheric scientists refer to as “small-scale, shear-induced atmospheric turbulence.” Basically, features in the landscape such as hills forest edge, and other structures disrupt the flow of wind which creates small areas of swirling wind that push or pull on objects moving through them. Turkey vultures fly with their wings in a dihedral, meaning looking head on at them, they hold their wings in a v shape. Vultures have relatively long broad wings with a light body. The long wings held in a v shape helps to stabilize them as the fly through these small areas of turbulence which may affect each wing differently. This is why we notice the characteristic rocking back and forth of the vulture’s flight. It’s a field mark that works even if the bird is a long distance away.
turkey vulture
Turkey vultures can effectively use these small atmospheric disturbances to move in weather like we had on Thursday. Even though 600 vultures were counted, very few hawks were seen. The hawks cannot take advantage of this type of wind as well as turkey vultures do so we don’t see many of the larger hawks moving in these conditions. Birds like falcons, accipiters, and harriers will soar, but they often do a lot of flapping also. If I see hawks moving early in the morning before thermals set up, it is usually these species.
Turkey vultures typically fly less than 50 yards up when using this method of flight. They are able to take advantage of small-scale turbulence so they can easily soar in less than desirable conditions and they have a strong sense of smell which at these low flight levels allows them to better seek prey. The next time you’re out and see turkey vultures soaring at low altitudes on a cloudy day you’ll know how they are doing it and why.
There could be some good migration depending on what the winds decide to do. Right now they are saying south winds Friday night changing to the north. There could be good migration until the winds switch. On Sunday, light southeast winds are predicted, which is not ideal, but could bring some birds in. Monday is supposed to be cloudy with southwest winds.
This weekend is not looking favorable for good hawk flight. Hawks want sunny skies and southwest winds, but Saturday and Sunday may see a switch to north winds along the lake about the time the hawks are getting going.
common loon
We have not had a lot of great days with south winds, so we may see quite a few birds. Expect some of the species that have recently showed up, but in larger numbers. We could also see yellow-rumped warblers and maybe even a pine or palm warbler. Early palm warblers are often the yellow or eastern race, so get a good look.
White pelicans are the birds to watch for as there have been a number of sightings throughout Ohio. They are still rare in the eastern half of Ohio, but have become regular visitors to the western half of the state in recent years. Over the last week, there have been reports of single birds in Cleveland, Eastlake, Mentor Marsh, Ashtabula Harbor and Conneaut. This may be the same bird moving around, but it is likely more than one. Birds have also been seen in the southern parts of Northeast Ohio.
belted kingfisher
Mute swans have been seen at Veterans Park in Mentor. This swan is not native to North America and has been a problem in many areas. They had nested in the past at Veterans Park, but have not been seen in recent years. While beautiful, they can be a hazard to other wildlife and people.
An immature laughing gull was observed along the lake at Lake Erie Bluffs on March 28—a very early date for a sighting of this species. Elsewhere along the lakefront, there have been reports of little gull, glaucous gull, Iceland gull and lesser black-backed gull, so gulls are definitely worth looking through for the more uncommon species.
Recent migrants have included great egret, sandhill crane, greater yellowlegs, Wilson’s snipe, yellow-bellied sapsucker, eastern phoebe, tree swallow, purple martin, brown creeper, golden-crowned kinglet, and savanna, vesper and fox sparrows.
Iceland gull