It’s hard to believe it’s been less than two months since crowds flocked to the Three Rivers Heritage Bike Trail to see the bald eagles fledge at Hays. A few dedicated eagle watchers still visit the site but this month they usually come up empty-handed. The young eagles have left for parts unknown and the adults lounge out of sight.
Boring as the eagles are right now, they’ve fostered a huge fan club and several reunions including a picnic last Saturday. Love for these birds has created many lasting friendships.
WQED’s Michael Bartley captured the excitement when he visited the bike trail in May. On site, he chatted with me about the eagles’ popularity and with the National Aviary’s Bob Mulvihill on what to expect from the eagle family in the weeks and months ahead. Though the video was filmed on a weekday in May you can see the trail was crowded with watchers.
As Michael says, “We haven’t seen the last of bald eagles in Pittsburgh. If you can’t wait til next year, here’s a look back at the birds that flew away with the city’s heart.”
Last week Marcy Cunkelman found a cedar waxwing nesting in her garden. For other birds, this would be a very late nest but for cedar waxwings it’s right on time.
Waxwings build their first nests in mid June when other birds have already fledged young. They start late because their main food source is sugary fruit and that’s not available until mid-summer. Yes, waxwings eat insects (have you seen them fly-catching?) but they only feed insects to their young during the first 1-2 days of life. After that they feed them mostly fruit.
This early August nest is the pair’s second brood. In order to complete the cycle before the end of summer Mrs. Waxwing starts building her second nest before the first “kids” have flown, on approximately Day 10 of their 15.5 days in the nest. By the time she finishes building, her first kids are fledging and she’s laying eggs.
She’s able to do this because her mate does the vast majority of the feedings. He feeds her on the nest and he feeds the “kids” until 6-10 days after they’ve fledged. In August he’s one busy bird!
Cedar waxwings’ dependence on fruit makes them highly nomadic with little site fidelity. They’ll nest where there’s lots of fruit — cherries, dogwoods, raspberries, crabapples, honeysuckle and ornamentals — and won’t come back if it’s gone.
Marcy has plenty of fruiting trees and shrubs in her garden. The waxwings obviously love it.
This year intrepid birders reported osprey nests in some unlikely places along Pittsburgh’s rivers.
Anne Marie Bosnyak monitored a nest near Neville Chemical on the Ohio River and last week Dana Nesiti followed up on a lead about a nest at the Union railyard in Duquesne.
On Thursday Dana went exploring and found the osprey nest atop an old power tower. There were three full grown youngsters in it. Look at the cables draped beneath the sticks. Talk about industrial!
Though his photos don’t show it, this nest is in an ugly spot that’s off-limits to all but railroad employees. To ospreys the lack of humans is just what they had in mind.
There are other advantages, too. Look east of Kennywood on Google Earth and you’ll see the railyard is on the Monongahela River near the Braddock Locks and Dam. The dam provides a variety of fishing opportunities in a very compressed space. There are lake-like conditions upstream, very active fish feeding in the turbulence below the dam, and fish resting in the quiet pools downstream. It’s a great spot for “fish hawks.”
When Dana arrived on Thursday he saw three juveniles in the nest but two of them could already fly. They put on a show.
…and flew by their nest-bound sibling.
On Friday, Dana returned to the site and was lucky to see the last of the three juveniles make his first flight. Here he goes!
The two Neville Island ospreys fledged, too. It’s been a successful year for “industrial” ospreys.
Because the barn swallow is very widespread and nests almost exclusively on man-made structures, it’s been easy to study this bird for a very long time. One interesting finding is that Hirundo rustica’s long tail streamers (outer edge tail feathers) are an excellent indicator of the birds’ health and a predictor of breeding success.
Birds with the longest and most symmetrical tail streamers are the healthiest and most desirable mates. According to Cornell’s Birds of North America, “Tail length tends to correlate with reproductive success, annual survival, propensity to engage in extra-pair copulation, parental effort, ability to withstand parasites, immunocompetence, and other measures of fitness.”
In other words, if you’re a barn swallow with a long symmetrical tail you’re really healthy, you get to choose the best mate, and your nest will be very successful. You’re also likely to be an older bird because tail length increases with age.
The down side is that long-tailed females are fickle. They always get the best mates but even when they’re paired up they often “mess around” with un-mated long-tailed guys. “Thus long-tailed male barn swallows are cuckolded more often than their less attractive neighbors,” says Frank B. Gill.
The longer the tail streamers, the better the bird. I’ll be watching their tails now.
This pair of prothonotary warblers at a nest box may give you the impression you can attract them to your yard if you install the proper box.
Surprising for a warbler, prothonotaries choose old woodpecker holes or nest boxes for their nests but they are picky about habitat. They only nest in forested bottomland, flooded river valleys or swamps.
The male returns from Central America before his lady and places nesting material inside his selected site. Often it’s over water. When his lady arrives he hopes she’ll agree that he’s chosen the right place. If she likes it she adds twigs, leaves, moss and rootlets to finish the nest.
You can’t convince this bird to nest in your back yard … unless your yard is a wooded swamp.
p.s. Thanks to Shawn Collins for the photo that sparked this topic.
(prothonotary warblers at Conneaut Marsh, photo by Shawn Collins)
These owls live in a part of the country were both eastern and western screech-owls occur. Cornell’s Birds of North America says the two species are so similar that they can only be distinguished from each other by bill color and voice.
Neither species migrates so ornithologists have been able to pinpoint their ranges. In Colorado eastern screech-owls live east of the Rockies, western screech-owls live west. Their ranges have a narrow contact zone in Colorado Springs but don’t overlap.
It’s a place where birders ask the screech-owls, “Whooo are you?”
The fact that it’s carrying dead grass tells us three things about this ovenbird:
It’s building a nest nearby,
It has a mate,
Back in 2004-2009 I participated in the second Pennsylvania Breeding Bird Atlas project in which we watched bird behavior and noted signs of breeding. We learned that a bird is probably breeding if it’s holding territory, courting, or becoming agitated as we approach. Its breeding is confirmed if the nest has eggs or young, or if we see an adult carrying food. (Did you know that most birds don’t bother to carry food unless they’re feeding young? *) The project was eye-opening because it forced us birders to slow down and observe what the birds are doing.
This ovenbird’s behavior — “Carrying Nest material (CN)” — is Confirmed or Probable nesting depending on the situation. It’s true that an ovenbird carrying nesting material is a female and she already has a mate, but this is not true of all species. In some, both sexes build the nest. In others, such as the Carolina wren, the males build several “test” nests and the females choose.
Among ovenbirds only the female builds the nest and she doesn’t bother to do it unless she has a mate. She chooses a depression of leaves on the ground and constructs a nest shaped like a beehive oven using grasses, plant fibers, weed stems, leaves, rootlets, mosses and bark. When completed the nest is so well-hidden that it’s invisible from above. Click here to see what the nest looks like with eggs inside.
Congratulations to Marcy Cunkelman on finding this ovenbird building a nest. What a cool photograph. I have never see this!
(photo by Marcy Cunkelman)
(* There are notable exceptions to the “carrying food” rule… worth learning.)
Mid-May is the height of robin nesting season in Pittsburgh. The first nestlings have hatched and some are ready to fledge.
On Thursday I saw my first-of-2014 robin fledgling in Schenley Park. Last month his mother spent 5-7 days building his nest. This video shows her process in only 8.5 minutes.
While Mr. Robin sings in the background, his mate brings dry grass and drops it into place. Her project looks sloppy for a while, then she does a cool thing. She rapidly stamps her feet inside the nest while holding the edges with her wings and tail. This makes the cup exactly fit her body. How cool is that!
Halfway through Mr. Robin comes for a brief inspection. Since he neither builds nor incubates, the nest is of passing interest to him.
When the cup is complete Mrs.Robin lines it with mud, then adds fine bits of dead grass to make the nest soft and lays her eggs. (The last two steps are not in the video.)
Robins raise two or three broods per year and usually build a new nest for each brood.