Pale Male was in some trees north of the Model Boat Pond when I arrived from Riverside Park late this afternoon. He soon flew to a “Linda” building railing and took advantage of the late afternoon sun. The dark female was on the nest and looked very settled in. Much more so, that the fidgety days of last week.
Thirty M.P.H. winds made it difficult to observe and photograph the nest Sunday afternoon, but there were positive signs that one or more eggs may have hatched. The mother ate on the nest and appeared to be sharing food. It wasn’t conclusive and she may have just been “eating for one”, but it did look like she might be feeding. We’ll know for sure in a few days.
The father joined the mother on the nest but there wasn’t an exchange. Another sign one or more eggs may have hatched.
The bad news is the adult male Riverside Park hawk ate a dead rat on Wednesday around the dumpsters where the Bromadiolone was placed. Reports on Wednesday were that the male seemed lethargic, but he seemed fine on Friday when I was in the park. Since the poison takes 5-7 days to take effect, we’ve got to keep our fingers crossed. Hopefully, the secondary dose from the rat was low enough not to cause harm to hawk.
Susan B. Elbin, Ph.D., Director of Conservation and Science, New York City Audubon passed along an article from Environmental Contamination and Toxicology, Anticoagulant Rodenticides in Three Owl Species from Western Canada, 1988–2003, Courtney A. Albert, Laurie K. Wilson, Pierre Mineau, Suzanne Trudeau, John E. Elliott. Among the topics the paper discussed was the potential under reporting of deaths caused by non-lethal doses of Anticoagulant Rodenticides. The authors believed that many non-lethal doses which cause lethargy, resulted in increased predation and “accidental” deaths due to collisions and car accidents.
I had always thought about poisons from a perspective of instant “Romeo and Juliet” style poisoning, rather then a more nuanced problem where the poisons act slowly and can cause secondary problems such as infertility in lower doses. Could the two highway accidents in 2009 have been a result not of inexperience fledglings misunderstanding traffic, but a result of non-lethal doses of Rodenticides making the hawks lethargic and therefore misjudging their flight paths? It’s impossible to know, but it does suggest that necropsies should be performed on urban hawks, even if cause of death seems obvious.
Now the excellent news… Both Glenn Phillips, Executive Director, New York City Audubon and Leslie Day, author of the Field Guide to the Natural World of New York City and Boat Basin resident have been having productive discussions with John Herrold, Riverside Park Administrator, Dr. Robert Corrigan, who is in charge of DOH’s rodent control program and Parks Commissioner Adrain Benepe.
From what I understand the discussions have been positive and both short term and long term results should be forthcoming. I can’t thank Glenn and Leslie enough for their efforts on behalf of the Riverside hawk pair. It’s clear that everyone involved is committed to finding a solution to this complicated issue.
Discussions have uncovered topics that weren’t entirely obvious. For example, while the Parks Department has a conservative approach to applying poisons, restaurants in the park are required by the Department of Health to have a rodent control plan. This introduces independent exterminators, who then potentially over apply poisons in the park without Parks Department supervision or oversight. (We saw this a few years ago at the Boat House Restaurant, which mirrored the situation at Riverside. At the Boat House improved sanitation has greatly decreased issues with rodents, and reduced the needs for poisons.)
It’s also been discovered that grass seed is being stored in the open in plastic bags on the lower garage level of the Boat Basin below the café and is attracting rats from the Amtrak train tunnel. Finding a better storage method should become a priority.
I spent about two hours watching the hawks on Friday afternoon. There were no signs the eggs had hatched yet. I saw the father circle overhead, but didn’t see him at the nest. (This isn’t unusual for this pair in the late afternoon.)
It looks like egg laying has started on Fifth Avenue, but the mother is acting a little inexperienced. She stood and preened after sunset for at least half an hour tonight. She may not have laid all of her eggs yet so “no worries”, but the behavior seemed out of place. I guess we have a young mother.
This is going to be a fun season. I suspect everything will be slightly different now that we have a new female.
The male at Washington Square was hard to find this afternoon. He only made a few appearances and flew towards Broadway at dusk. The tall buildings on the square make it difficult to figure out where he goes, and how large the territory is. Could it be as far east as Tompkins Square? How far into the Village? Does it go south to Houston?
The Dark Female (Ginger/Lima) spend another night on the nest this evening. Around 7:40 p.m. she circled the area of the hawk bench and then landed on the nest.
My original hypothesis about this year’s nesting seems to be holding true. I thought that the Dark Female, who was hanging around with a young hawk who she stole food from, didn’t yet have the hormones to bond properly with Pale Male in January.
This allowed the Pale Female (Pale Beauty) to come in and try to bond with Pale Male later in the season. But I think she was too young to lay eggs yet, so things didn’t work out. She never seemed interested in the nest. I believe this allowed the Dark Female, who was now more motivated to mate since the days were much longer, to move in and displace her.
Even though it was late in the season, I wasn’t concerned. Triggers other than longer days must play a part in getting a female to ovulate. This must include copulation, nest building, constant displays of food by the male, etc. With help from other hawk watchers, we estimated that it would take three to four weeks for the Dark Female to ovulate from the date of her return. It’s been sixteen days since the Dark Female returned, and now our timing estimates look like they might be correct. I certainly hope so!
