What’s that noise in the backyard tonight? Who’s out there?
In autumn in Pennsylvania, great horned owls (Bubo viginianus) call to establish territory and court their mates. Their family time is coming soon. She’ll lay eggs before any other raptor species, sometimes as early as December.
Listen for their 5-note syncopated call: “hu-hu-Hoo HOO HOO“
If you’re lucky you’ll hear them “sing” a duet. (Turn up your speakers to hear both birds in this recording. The male’s voice is the lower one.)
Anywhere you live in North America, if there are woods or fields nearby great horned owls are there year round.
By last Sunday, 11 Nov 2018, a gap in the trees revealed an eagle on the nest. Click the screenshot below (arrow added) or on the caption to see Dana Nesiti’s video from Eagles of Hays PA Facebook page.
Hays isn’t the only site where nest renovations are in progress. The eagles at Canonsburg Lake in Washington County have been bringing sticks, too. Rich McPeek caught one in the act on Veterans Day and posted it on the Canonsburg Lake Eagles Facebook page.
And in Butler County, Steve Gosser found this adult bald eagle cruising at Moraine State Park on Veterans Day.
I’m sure there’s bald eagle activity at Dashields Dam and Harmar but I’ve heard no news from those sites. Meanwhile, check out the eagles at North Park Lake. They may be up to something. 😉
Mid-September is the peak of broad-winged hawk migration in Pennsylvania as these woodland raptors head for the forests of Central and South America.
Broad-winged hawks (Buteo platypterus) breed in North American forests but spend only four months of the year up here. In late August they start to move south, reaching the forests in Central and South America by early November.
What’s unusual about broad-wings is that they travel in flocks — most raptors don’t — and they watch each other for flight cues. If one finds a thermal with good lift, others join him and rise on it as well. Soon they form a “kettle” of hawks stirring round and round in the rising air. As each one reaches sufficient altitude it sets its wings and glides south to find the next thermal.
If the weather’s good this weekend, hundreds if not thousands of broad-wings will kettle up and stream out over hawk watches in the Mid-Atlantic. Here’s what it looks like on a good day, recorded at Ashland Hawk Watch in Hockessin, Delaware on September 15, 2013.
Bald eagles have made an amazing comeback since the days of DDT. From less than 900 birds nationwide in the early 1960s to more than 20,000 in the U.S. in 2007, their population more than doubled in Pennsylvania in the last 10 years.
At some point the number of nesting bald eagles will reach Pennsylvania’s carrying capacity. What happens then? How do bald eagles respond to match available food and nest sites? We can look to Virginia for the answer.
Since 1964 the Center for Conservation Biology in Williamsburg has monitored and mapped bald eagle nests in the James River watershed. Every year they do a flyover of the entire area to count both nests and chicks. Their eagle population grew from none in 1976 to a record 289 nests in 2018. Meanwhile the number of chicks per nest — called “productivity” — rose sharply in the early years of recovery and now is dropping. CCB announced this trend in two articles:
“Productivity decline” sounds bad but it’s actually good news. Breeding eagles respond naturally to accommodate lots of adults in the habitat.
So what does this mean for Pennsylvania’s bald eagles?
If the James River experience applies here, we’ll still see an increasing number of bald eagle nests that will eventually average one eaglet per nest. We know bald eagles can produce more if they need to. The good news is, they don’t need to.
Last week in Newfoundland our birding tour witnessed an amazing bird interaction when a merlin attacked a big black corvid in the air. It happened so fast that we had to think hard about the birds’ identities.
Yes the attacker was a merlin — a small, streaky dark, very fast falcon that made this sound as it attacked. (Xeno-canto XC332445: alarm calls of merlin pair recorded by Pritam Baruah in Churchill, MB, August 2016)
But was the big black bird a crow or a raven?
Fellow traveler Trina Anderson captured the action with her camera. Before we saw her photos we could only identify the corvid by size and behavior. We decided “raven” based on the relative size of the two birds and the behavior of the raven.
Merlins are 2/3 the size of a crow but less than half the size of a raven. Overhead the merlin was tiny compared to the bird it attacked, so it had to be a raven. Trina’s photos show the size difference.
The black bird barely flapped during the interaction and it flipped upside down in flight (see the last photo). Crows flap hard when they’re under attack and they don’t fly upside down.
During the fight it was hard to see the diagnostic field mark — the tail — but Trina’s next photo shows the corvid has a wedge-shaped tail. That means “raven.”
It’s hard to tell ravens from crows unless you have some practice. Get tips on how to tell them apart in this 3 minute video from The Raven Diaries: Ravens vs Crows, they’re different!
In Pittsburgh we’re lucky to have three bald eagle nests in Allegheny County: Hays on the Monongahela River, Harmar on the Allegheny River, and Crescent Township on the Ohio River.
Last weekend the two youngsters at the Harmar nest made their first flight. Annette and Gerry Devinney were on hand to record their progress on 1 July 2018. Here are some of Annette’s photos and Gerry’s video.
Below, the two young eagles fly near each other. They’re looking good.
Woo hoo! They’re playing in the sky.
Gerry captured their soaring and antics in this video.
We often complain when birds of prey eat “our” songbirds, rabbits, chipmunks and squirrels but there’s one prey item that no one quarrels about.
Last weekend Dana Nesiti posted a photo series at Eagles of Hays PA: The mother bald eagle brought food for her fledgling, H8, who quickly crowded her and grabbed for it. The prey was nearly lost in the scuffle. (click here for the photo album)
What did she bring him for dinner? A rat!
Thank goodness birds of prey are eating rats. I’ve seen red-tailed hawks eat them, too.
The airspace over Greenfield was busy with bird traffic on Sunday. One of those birds was in control.
Around noon Anne Marie Bosnyak, Linda Schmidt and I were chatting at a table outside the Staghorn Cafe when Anne Marie pointed out four distant turkey vultures. She’d left her binoculars in the car so she wasn’t sure about the fourth one. With my binoculars I identified it — a peregrine falcon. At that distance I couldn’t tell if it was immature or adult.
Most birds avoid flying near peregrines because of their swift pursuit of avian prey and fierce territoriality. The vultures were no exception. They circled together and moved westward, away from the peregrine heading south.
The peregrine rose in the heated air, then noticed a pair of dark birds rapidly heading west and turned to follow them.
Ravens. As if to acknowledge the peregrine’s presence one of them tumbled three times in the sky but they didn’t slow down. The ravens left without incident.
The peregrine circled lazily in the heat and then something really interesting flew below him — an adult bald eagle heading toward the Monongahela River.
As I watched, the peregrine dove several times at the bald eagle and drove it lower and away. Even through binoculars I could see the eagle flinch as it tried to evade the peregrine. They disappeared over the horizon toward Hays.
In Pennsylvania peregrine falcons control the airspace whenever they want to. Bald eagles don’t stand a chance, as shown in Peter Bell’s photo above.
If you miss seeing nesting peregrines on camera here’s a raptor family to watch online. As of last night (June 5), there were two chicks and one egg still to go at an osprey nest in Montana.
The nest is in Hellgate Canyon next to the Clark Fork River in Missoula, Montana. It looks like a very public place but the birds are right next to the river. The Hellgate valley is so narrow here that the river, the railroad, some businesses, and Interstate 90 are all close by. We see and hear I-90 traffic in the background. (Click here for a map of the site.)