Just like brown-headed cowbirds (Molothrus ater), common cuckoos (Cuculus canorus) in Eurasia are obligate brood parasites that never raise their young. Cuckoos lay their eggs in the nests of smaller birds that foster the cuckoo chicks as their own. A stark difference between cowbirds and cuckoos, though, is their size. Cuckoo chicks can be 10 times larger than their hosts!
So if you think cowbirds are bad, consider common cuckoos.
p.s. I asked folks to tell me the identity of the foster parent standing on the chick’s back. Janet Campagna suggests meadow pipit — which looks right to me. Meadow pipits are one of three species most often parasitized by common cuckoos.
(photos from Wikimedia Commons plus an embedded photo from Twitter; click on the captions/tweet to see the originals)
On a late July visit to Washington’s Landing (Herr’s Island) I saw two song sparrow families with begging fledglings. Unfortunately the begging youngsters were brown-headed cowbirds, not song sparrows.
Female brown-headed cowbirds lay their eggs in the nests of smaller birds. Each cowbird chick is raised, not by its own mother, but by foster parents of another species. To make matters worse, cowbird parents lurk near the foster nest to make sure their own baby survives. They remove the host’s eggs or kill the foster parents’ young to give their own chick a better chance.
Cowbirds parasitize many species but are especially fond of song sparrows and yellow warblers. Yellow warblers are well aware of cowbird eggs and will “abandon” the nest by building a new nest on top of the old one. Experienced song sparrows get upset but don’t have an immediate solution.
However, song sparrows have a secret weapon — their breeding season is longer. Their first of two to four broods may begin before cowbirds are ready to lay eggs while the last nest starts after cowbirds are done.
In Pennsylvania brown-headed cowbirds stop laying in early July while song sparrows are still going strong. What I saw at Washington’s Landing was this year’s last round of cowbird babies.
(photo from Wikimedia Commons; click on the caption to see the original)
Last Friday Mary Ann Pike noticed that Terzo and Morela were spending a lot of time at the Pitt peregrine nest and commented:
Seems like Morela and Terzo have been swapping shifts at the nest today. I saw Morela this morning, then Terzo early afternoon for a while, now Morela is there again. What a strange situation with Ecco in the mix. I wonder if he hangs around Oakland somewhere when he’s not on camera. It seems like the other 2 must be spending most of their time in Oakland but under normal circumstances they wouldn’t let a third Peregrine hang around.
We didn’t realize it on Friday but Terzo and Morela were probably vigilant because Ecco was nearby. He appeared on camera before dawn.
In the video below Ecco arrives at 5:33am to bow with Morela. After he leaves Morela pauses for 45 seconds, then we hear a peregrine wailing at 3:28 in the video. The wailing continues intermittently over the next three minutes. Was it Terzo complaining that Ecco was there?
The rest of 24 July was very busy. Morela and Terzo bowed at 8:30a and 3:30p.
Terzo sunbathed and watched for two hours.
Then Morela hung out and preened for three hours. I’m happy to see that Morela’s flipped primary feather is gone.
Terzo and Morela courted at dawn on Sunday morning. There was no sign of Ecco but I’m sure he’ll return.
However, the threesome continues at the Pitt peregrine nest.
Something is happening among nesting bald eagles in the James River watershed that may explain what we’re seeing among peregrines in western Pennsylvania. There are lots of eagles at the James River but less nesting success than in the past. The Center for Conservation Biology in Williamsburg, Virginia has figured out why.
CCB has been conducting bald eagle nesting surveys every March since the 1970s. Seven years after DDT was banned they found only one pair of bald eagles in the watershed. This year there are 319 pairs.
Lower nesting success is not a food problem, it’s a competition problem. CCB explains:
The mechanism causing the decline does not appear to be traditional resource competition where pairs scramble for their share of limited fish. Rather, the mechanism appears to be young marauding eagles that are disrupting territory holders and competing for a limited set of viable breeding territories.
Young bald eagles are harassing adult pairs in an attempt to gain a territory — so much so that some pairs fail to nest successfully.
This month a pair of song sparrows is nesting in a hanging basket above Bob Donnan’s deck in southwestern Pennsylvania. Bob wanted to see them better without disturbing them, so he set up a nest camera and is publishing YouTube videos of their activity. This week the babies grew a lot.
Bob’s 12 July 2020 video opens with both parents feeding four nestlings. Only about three days old, the nestlings are featherless and their eyes are closed. After the feeding ‘papa’ bird leaves while ‘mama’ remains to tidy the nest. She picks up something that looks like a worm and eats it — a fecal sac from one of her nestlings.
It’s almost mid-July yet two peregrine falcons, Ecco and Morela, are pair bonding at the Pitt peregrine nest in a very serious way. On Saturday 11 July they courted twice and touched beaks in a close bond before dawn.
I should have seen him coming. My first hint was when Morela spent five hours roosting at the nest rail on the night of 8-9 July from 9p to 2a. Female peregrines usually don’t roost at the nest outside the breeding season. Here she is on the 8 July 2020 “Night in a Minute” video.
The next morning, Morela and Ecco courted for almost four minutes.
The 10th of July was quiet but they returned before dawn on 11 July, courting for three minutes and touching beaks. Beak-touching is more intimate than merely bowing. These two are hitting it off as a couple.
Less than three hours later, at 8:27a, Morela returned with a full crop and courted with Ecco for another three minutes.
I don’t put a lot of stock in the permanence of Morela’s bond with Ecco since he and Terzo trade places so often. However, it’s intriguing to see that she’s so close to Ecco.
Meanwhile, here’s something to ponder …
Why does Morela have a flipped primary feather?
Female peregrines usually molt their primaries during incubation (April/May) so I was surprised to see one of Morela’s primaries is flipped on her right wing. The feather was normal until the morning of 27 June when Morela returned to the nest rail. She preened and stayed there for five hours as shown in the Day in a Minute video .
So far the flipped feather has stayed in that position for 16 days. If it had flipped due to molting, the new feather would have pushed it out by now. So I wonder, was Morela in an aerial battle on 27 June? Even if we knew the answer, we’ll never know who her adversary was.
(photos and video from the National Aviary falconcam at Univ of Pittsburgh)
For such a tiny shorebird, male piping plovers (Charadrius melodus) have an elaborate courtship dance. The best part of it — the “tattoo” — was tweeted last Friday by the Ontario Piping Plover Conservation Program.
You might hear about fancy mating dances done by birds in the tropics. Piping Plovers have one too! Goose stepping (tattooing) is a courtship dance done by the male right before copulation. The female rejects or accepts this dance! ? Video by Plover Lovers pic.twitter.com/0zyKH54fgW
— Ontario Piping Plover Conservation Program (@ontarioplovers) July 3, 2020
This spring the unresolved rivalry between two male peregrines — Terzo and Ecco — at the Cathedral of Learning made for a disappointing nesting season but generated a lot of speculation. Now that we know more about the Downtown peregrines we can lay one bit of speculation to rest.
Back on 15 March when Terzo and Ecco’s rivalry was spinning like a revolving door, I was surprised to see the Downtown female peregrine Dori appear on camera at Pitt. At the time I couldn’t help wondering, “Is the unbanded male Dori’s new mate who is shopping in Oakland because he doesn’t like the Downtown site?” … This led to speculation that Ecco was two-timing between the two nests. No, he is not.
Ecco has not been two-timing between Pitt and Downtown because (1) he’s not Dori’s mate and (2) he would have been way too busy Downtown to visit Morela at certain critical times.
Meanwhile at Pitt, Ecco spent a busy day courting Morela multiple times on 25 June.
Even if we didn’t know Dori’s real mate, this timing indicates Ecco has nothing to do with the Downtown nest.
So, Ecco isn’t two-timing. Frankly he’s having trouble being a successful one-timer.
My apologies for sending us all down this speculative rabbit hole. I should have brushed off Dori’s visit as curiosity on her part. I’ve seen other females visit the Pitt nest during turbulent times. Magnum visited twice in 2016 during Hope’s first turbulent year.
As much as I know peregrines I never learn that they’re surprising.
(photos from the National Aviary falconcam at Univ of Pittsburgh and Lori Maggio)