At long last I've created a slideshow of the best peregrine photos from the Gulf Tower's 2010 nesting season.
It was a big year. On March 20 Tasha, the long-standing female at Gulf, lost her nest to Dori even though she'd already laid two eggs in it. On April 2 Dori began laying her own eggs next to Tasha's and by April 7 the nest held five eggs from two mothers. All five nestlings fledged and only one, Blue Girl, is known to have died. Quite a successful year for all that drama!
I tried to pack everything into the slideshow but it was hard. The picture above didn't make the cut, but you'll like it. It shows Dori and Louie getting to know each other. Louie had just brought Dori (at left) a huge, tasty meal which is now bulging in her crop (notice her throat!). Now that she's been fed they're bowing to cement their pair bond. Behind Louie you can almost see Tasha's two eggs waiting to be joined by Dori's three.
Click on their picture to watch the slideshow.
Special thanks to everyone who sent me images from the webcam last spring and to Jim Altier and Sharon Leadbitter for contributing their photos.
(photos in the slideshow are from the National Aviary Gulf Tower webcam, Jim Altier and Sharon Leadbitter)
Believe it or not, Spring is on its way. Chuck Tague found a great horned owl nesting last week at Merritt Island, Florida.
You're probably thinking, "Of course owls nest in Florida in January. It's warm there." But these birds are more versatile than you think.
Great horned owls are the first birds to nest in Pennsylvania each year. They start courting in late fall and become really intense in December and January when you often hear them hooting in the woods and suburbs. By February they've chosen a nest site and the female lays her eggs.
Nest site selection is almost amusing. In Pennsylvania great horned owls often choose the tops of broken-off hollow trees but they also like stick nests, though they never build their own. Instead they usurp an old red-tailed hawk nest or, in this case, an osprey nest. No contest. The original owners are gone. Even if present they wouldn't tangle with this lady!
And yes, that's the female's telltale "horns" sticking up. She does all the incubation.
Their secret to winter nesting success is that the female keeps the eggs at a constant 98.6oF even when it's -27oF outside. She closely incubates the eggs for 30-37 days while her mate does all the hunting. He brings her food at night.
So keep your eyes and ears open for great horned owl activity this month. You might find out where they plan to nest, but don't get too close. You won't want to tangle with Mama!
After last weekend's thaw we've returned to the amount of snow we had before it rained -- about an inch or two on the ground in Pittsburgh -- with another inch+ expected today.
North of I-80 it's another story. By Wednesday the Pymatuning area already had an inch of fluffy stuff but now they're expecting 2-4 inches of snow today, 3-5 more inches tonight and an additional 1-3 inches on Sunday.
I was going to go birding at Pymatuning tomorrow but that news changed my mind!
So I'm keeping my feeders filled and hoping for a pretty scene like this one.
One of the fascinating things about birds is that each species is specialized and it's expressed in so many ways, even in their feet.
A couple of days ago fellow birder Bill Parker sent an email in which he mused on the length of birds' rear toes with photos to illustrate. He said, "I was noticing in one photo that the Snow Bunting has really long rear toes."
As you see in Bill's pictures the rear toe, or hallux, on the golden-crowned sparrow (left) is normal for a perching bird, it appears to be missing on the sanderling (middle), and it's very long on the snow bunting (right). I'd blogged about the position of the toes but I'd never thought about their length so I did some research.
It turns out that rear toes are highly variable. Many wading and water birds have a vestigial hallux that's so high on the metatarsus and so short that it doesn't touch the ground. That's what happened to the sanderling.
But there are exceptions. On cormorants the rear toes face (vaguely) forward and are webbed with the other three. On kittiwakes the fourth toe is gone.
Birds' toes indicate their lifestyle. Sparrows perch a lot so they need a grasping hallux. Sanderlings walk on the beach (a lot!) so they don't need rear toes. And snow buntings are perching birds who wear snowshoes.
Even we could use a hallux sometimes. "When I've been on a ladder painting, I've wished for a rear toe like the Snow Bunting," said Bill.
Check out the jacana's toes. They'll certainly keep you on a ladder!
Bald eagles have made a stunning comeback in Pennsylvania since the 1960's when only a couple of nesting pairs survived DDT. There are now at least 174 nesting pairs in the state.
We know these numbers because of the PA Game Commission's careful management of the species and because of the Midwinter Bald Eagle Survey which is happening right now across the lower 48 states (except Florida), December 29 through January 12.
Unlike the Christmas Bird Count, the Midwinter Bald Eagle Survey has pre-defined routes assigned by a statewide coordinator and most of the participants are state and federal wildlife employees. It's a very precise, scientific survey which does not change locations from year to year. The goal is to count the same way every year without overlap. Click here to read more.
Why count in the dead of winter? January is a great time to see bald eagles because the trees are bare and the birds are courting, building nests and roosting for warmth. This year the PA Game Commission is especially interested in the roost sites because it's important to preserve them as winter habitat.
Habitat preservation is an important part of the PA Game Commission's bald eagle management plan. The birds are now so numerous that they can be de-listed in Pennsylvania but this success will only continue if we are careful not to undermine what we have today. Toward that end the PGC has published a Draft Bald Eagle Management Plan for 2010 to 2019. It's a fascinating document that describes the bald eagle's lifestyle, its history in the state, and PGC's plan for making sure we have plenty of eagles in years to come.
You can read the draft management plan here and send your comments through March 3.
Check out the plan to see what's going on with our eagles. They really count in Pennsylvania!
Here's a winter weed you really need to know about!
Without its "leaves of three" poison ivy looks very different in winter but its vine, berries and roots can still give you a rash. Here are some photos and tips on how to identify it.
First and best clue: The vine looks hairy. If you see a vine like the one in this picture, don't touch it, not even with your mitten!
Next clue: The branches are stiff, a little crooked and mostly horizontal. Sometimes the plant grows as a low shrub or as stand-alone sticks so the branches do stand up, but they still have that little crooked look.
A thriving patch of poison ivy can completely engulf a tree and when it does its branches reach out quite far. I call them "devil's arms" because they look like they're reaching out to get me. Look how long they are here!
Third clue: The clumps you see on those "devil's arms" are poison ivy berries. They look like bunches of tiny white grapes, easy to see in the photo below.
Birds eat the berries throughout the winter so the clumps will slowly disappear, leaving the branches bare. It's amazing that birds and other mammals don't get a rash from poison ivy. Only we do.
So watch out for a hairy vine! Don't touch those white berries! Don't dig up the root!
Even though it's winter you can still get a rash from this plant.
For more information on poison ivy, see this blog and its links and comments.
On Saturday I counted birds in my neighborhood for the Pittsburgh Christmas Bird Count on the wettest, rainiest day we've had in a very long time. The only birds that moved were crows, starlings and pigeons.
The pigeons caught my attention because they were so hard to count. Just after dawn a flock of two dozen birds began their morning flight routine. They started off slowly but as they warmed up they flew in tighter formation, faster and faster, closer and closer together, changing direction often. I marveled at how well they stayed in sync. They were very hard to count!
At the height of their exercise I noticed the flock changed direction so quickly that the leader must have ended up in the back of the group. How did they do this and still maintain their formation? Who was in charge?
This question has puzzled scientists too, so last year a team in Budapest decided to find out more by attaching GPS backpacks to a flock of domestic homing pigeons. The GPS units recorded the birds' position every 0.2 seconds as they flew home or wheeled around the neighborhood. The data was then used to plot the birds' paths and figure out where each bird flew in relationship to the others and how quickly it changed direction in response to the rest of the flock.
The results were quite interesting. The flocks' leaders almost always fly in the front and the other birds copy the leader's movements within 0.4 seconds. The low ranking birds fly behind and to the right but leadership can change and even low-ranking birds occasionally get the chance to lead. This confirms my hunch that the leaders end up at the back of the flock sometimes.
Why do the low-ranking birds fly behind and to the right? The researchers' theory is that this position maximizes their ability to follow the leader. These birds use their left eyes to watch the leader, left-eye information is processed by the right side of the brain, and the right side of the brain is best at quickly handling social responses.
Why does the flock change leadership? How does it hand off leadership so deftly? The study didn't answer all my questions but it's a great start. Read more about it here in Science Magazine.
(photo from Wikimedia Commons. Click on the image to see the original)