Pigeons (Columba livia) and the raptors who hunt them have evolved together for millions of years. The raptors’ successful hunts leave only the fastest, most maneuverable pigeons. Speedy, elusive pigeons mean only the most skillful raptors can survive. Most of us never get to see this interaction so this dramatic video from Romania is a real treat.
The pigeons stay in a tight flock because raptors can’t pick out a victim in a moving ball of birds. The raptors try to separate one bird from the group by slicing through the flock. If it works, the raptor pursues the lone bird.
Here’s a bird you won’t see in Pennsylvania. He was photographed at Carrizo Plain National Monument, 100 miles (as the crow flies) northwest of Los Angeles, California.
Quiz: Who is this on the wire? … Notice his long legs.
(photo by Bob Wick, BLM via Wikimedia Commons; click on the caption to see the original)
Earlier this month we watched expert falconer Lloyd Buck fly his peregrine falcons in The World’s Fastest Animal on NOVA. Here he is in a 6+ minute video putting a northern goshawk through her paces. Watch her perform in slow motion.
You’ll probably notice how similar the northern goshawk is to a peregrine falcon. The two species aren’t closely related but they need similar skills to survive, so their bodies and actions are similar, too. The difference is that the goshawk doesn’t dive on prey like a peregrine. The goshawk always chases.
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“
With leaves on the trees in October, it was hard to see the new nest when one of them flew in –> see Gerry Devinney’s video, 6 Oct 2018.
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.
Bald eagle at Crooked Creek, 11 Nov 2018 (photo by Steve Gosser)
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.
Make plans to visit a hawk watch soon. Here’s how to find one near you: Hawk Watch Information
Juvenile bald eagle at Hays, H8, 23 June 2018 (photo by Dana Nesiti)
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:
To see how this works, I have made a slideshow of two graphs from the Center for Conservation Biology’s article. The bar chart is the count of nesting pairs, 0 to 289. The line chart, the arc, is the average number of chicks per nest, 0 to 1.6.
As you can see, the number of nesting pairs continues to increase while the number of chicks per nest moves down.
“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.
Merlin attacks a raven at Renews, NL, 10 July 2018 (photo by Trina Anderson)
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.”
Merlin attacks raven, Renews, NL, 10 July 2018 (photo by Trina Anderson)
Merlin attacks! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)
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!
Captain Ray with a fish (photo by Chris Colaianni)
On Throw Back Thursday:
Eight years ago Chris Colaianni went on a fishing trip in the Canadian Rockies and came back with this amazing story.
Their guide, Captain Ray, used a fish to attract a bird. But why does he have the fish in his mouth? Click here to find out in this vintage article: WHAT Is He Doing?
