Blakeman on the new Riverside nest

Riverside Park redtail in new nest -- May 21, 2008
Photo by Leslie Day


John Blakeman, the Ohio redtail expert, sends in an opinion about the new Riverside nest:

Marie,

I'm extremely pleased to see the new Riverside nest in the plane tree crotch.

This reveals several very positive conditions -- ones that I believe override the legitimate concerns regarding the rat poison.

First, the birds have learned their lesson. The first nest site, way out on the thin limbs, was a failure. The site was poorly selected -- but the adults were doing this for the first time, merely following instinctive tendencies.

This is now a classically typical and perfect Red-tail nest site. Only an outright tornado or hurricane could dislodge this new structure. Nice work.

Secondly, it went up very quickly, in apparently just a few days. This indicates that the pair has very strong behavioral motivations to continue with nesting this spring. Even if no eggs are laid at this somewhat late date, the birds are already strongly set up for vigorous nesting nest year. These birds aren't going anywhere else to nest next season.

Because there were three strong eyasses, there was an ample supply of food (albeit poisoned in one case). The formel may thereby be able to lay another fertile egg or two. Copulation is already being reported, so an egg may soon begin to descend the bird's ovary.

There could be incubation within 10 days or less. If so, there is a very good chance that more eyasses can be seen this year. If the poisoned rat problem doesn't recur, new eyasses could fledge from this nest this year.

There is no way of knowing if this will happen just yet. But clearly, this pair has learned how to build a proper nest. They already know how to brood and feed.

So let's see what happens. This could be good.

***************************************************************************
PS: Good news has just come in from Riverside Park hawkwatcher Emma Cobb:

Crista Carmody, the park manager at RP, has informed us that the Boat Basin Cafe will not be permitted to use pesticides of any kind in the outdoor areas of the restaurant.

Rat Poison has killed other Red-tailed Hawks -- and an important PS

The new nest under construction in Riverside Park - May 21, 2008
Courtesy of PaleMale.com
[Note that this young pair of redtails have constructed the 2nd nest in the crotch of a London Plane, not on the edge of a branch as they did in nest#1. Quick learners.

It has become clear the the Riverside Park chicks were poisoned by an anticoagulant of the type commonly used in rodenticides. A website correspondent from Michigan, Debbie Olsen, alerted me to the following article:

Anticoagulant Rodenticide Exposure in Birds of Prey in Massachusetts

Anticoagulant rodenticides are used to control rodent populations in various settings, including urban, suburban, and agricultural areas. These rodenticides disrupt blood clotting pathways, resulting in excessive bleeding and death. While effective in controlling rodent overpopulation, these poisons can also cause mortality in non-target species of mammals and birds that ingest the bait (primary exposure) or ingest poisoned animals (secondary exposure).

Brodifacoum is a second-generation anticoagulant rodenticide that is currently available for household use in a variety of forms, including bait blocks and pellets. This compound presents a high risk for unintended poisoning of wildlife due its long persistence time in liver tissue. Brodifacoum is the rodenticide that has been identified in birds of prey suffering from anticoagulant rodenticide toxicosis that have been treated at Tufts Wildlife Clinic (TWC).

The most frequent species treated at TWC for anticoagulant rodenticide toxicosis is the red-tailed hawk (Buteo jamaicensis), which predominantly feeds on small- to medium-sized mammals but will also consume birds. Affected hawks present extremely anemic and weak with evidence of profuse bleeding from minor lacerations or extensive bruising with no evidence of serious traumatic injuries such as fractures. If these birds are not found and treated they will die due to blood loss. However, if they are found in time and receive aggressive medical treatment for blood loss and the antidote for the rodenticide (Vitamin K 1), they can recover and be released back to the wild.

The clinical cases treated at TWC, together with reports on widespread anticoagulant rodenticide exposure in birds of prey in New York state, led to this ongoing project intended to survey the extent of exposure of birds of prey in urban and suburban areas of Massachusetts to these compounds. Species included in this study are red-tailed hawks, barred owls (Strix varia), eastern screech owls (Otus asio), and great horned owls (Bubo virginianus).

Documenting the presence of these rodenticides in predators such as birds of prey reflects the far-reaching effects of human activity on environmental health. As rodent populations flourish in human-altered landscapes, attempts to control these populations have potential consequences for animals higher in the food chain. This project, therefore, demonstrates a fundamental concept of conservation medicine: the interconnectedness of humans, animals, and ecosystems.

Principal Investigator: Maureen Murray, D.V.M.

Co-Investigator: Florina Tseng, D.V.M.

Project Funder: Animal Welfare Institute

References:

Murray M. and Tseng F. In Press. Diagnosis and Treatment of Secondary Anticoagulant Rodenticide Toxicosis in a Red-tailed Hawk ( Buteo jamaicensis ). Journal of Avian Medicine and Surgery.

Stone,W.B., J.C. Okoniewski, and J.R. Stedelin. 2003. Anticoagulant rodenticides and raptors: recent findings from New York, 1998-2001. Bull Environ Contam Toxicol. 70:34-40.

The item comes from the Tufts University - Cummings School of Veterinary Medicine -- URL: http://www.tufts.edu/vet/wildlife/rodenticide.html


PS I spoke at some length yesterday with Glenn Phillips, the executive Director of NYC Audubon.

Egg retrieval
We discussed plans for egg retrieval at the Fifth Avenue nest Soon! Perhaps next week. Why the delay? The building is sending up a window-washer platform next week for facade work. The workers will remove the eggs. This will save NYCA the $15,000 cost of hiring its own removal crew. And, according to Phillips, it may not be too late for the diploidy test, the one that could reveal whether the eggs in the nest were fertilized].

MBPM-2
We discussed the Memorandum interpreting the Migratory Bird Treaty Act. MBPM-2 -- issued by the US Fish & Wildlife Service in April 2003. This was the Memo that facilitated the removal of Pale Male's nest in 2004. I have been strongly in favor of a fight to remove this Memorandum from the books. Phillips explained NYCA's complicated stand on this issue -- and why they believe working for the removal of MBPM-2 might not be the way to go. He was quite convincing. [More on this at a later date].

Rat Poisons
We also discussed the rat-poisoning issue . I understand that neither Central Park nor Riverside Park use the anticoagulant-type of rodenticide. Therefore it is likely that the stuff involved in the Riverside Park poisonings was put out by some nearby building to control rats in their basement or around their garbage areas.
Consequently NYCA is planning an education campaign for all buildings on the periphery of Central Park and Riverside Park, to inform building managements of the dangers to local wildlife of using toxic rodenticides.

NB: Concessions within Central Park [Tavern on the Green, the Boathouse] and Riverside Park [various Cafes] do not observe the same rules as the parks do. We have to find out just who sets the rat-baiting rules for them -- it remains unclear. That they use powerful rodenticides is certain.

Bad news and good

[Can't upload photos this morning for some reason. Photo of new nest in Riverside Park available at http://www.PaleMale.com. ]


Many of you have already heard the bad part of this news from other websites. The good news may be new to some. Leslie Day, one of the most dedicated of the Riverside Park hawkwatchers and author of the recent Field Guide to the Natural World of NYC, sums it up:


[the bad news]
"The toxicology report is back from the analysis of the first hawk carcass: hemorrhaging of the lungs due to a rodenticide anticoagulant. So the parents fed their babies a poisoned rat. Look at palemale.com for further information.

[the good news]
I was walking my dog north along the lower promenade just past the northern-most marina gate past a row of London planes when I saw one of our hawks land in a sweet gum tree and start jumping up and down on a branch. I looked around and to my total astonishment saw a HUGE nest against the trunk of a London plane. It is supported by 4 or 5 very large branches and looks like they have been building it for at least 10 days. Lincoln saw them mating after the catastrophe. He told me today that after one of Pale Male's nest failures, they started building again right away. "

This may be the first documented instance of hawk mortality directly attributable to a NYC park's use of rodenticides. [One of Pale Male's previous mates died after ingesting a powerful chemical used to get rid of pigeons -- it was put out by a local building, not the Parks dep't].
You can be sure there will be a concerted effort on the part of the Nature Communities of both Riverside and Central Parks, to do something about this situation. We have been vocal about the use of these anticoagulant substances for years. Indeed, thanks to hawkwatcher efforts, Central Park suspended the use of the various rodenticides in the vicinity of the Model-boat Pond during the years Pale Male's nest was producing chicks.
The mandatory labels on the packages of these rodenticides used by the parks declare that they produce no "secondary effects". In other words, the manufacturers claim that there is scientific evidence showing that the substance will NOT effect any wildlife that eats an affected rodent. Obviously, now, this claim is not true for the anticoagulant that killed the three Riverside Park nestlings.

I'll be posting more on the rat-poisoning issue soon. It will not just go away, I promise you. It has been a hawkwatcher concern from the first year [1993] that Pale Male nested on Fifth Avenue. It rather amazes me, now that I think of it, that there have been no earlier incidents like this one, during the fifteen years hawks have been nesting in areas around the city where rodent-baiting is practiced . It will be very interesting indeed to find out, if possible, the name of the exact substance that proved fatal to the Riverside hawklets. Perhaps it was something new or different. Meanwhile, it is important to note that the report from Ward Stone at the DEC [via Palemale.com] was preliminary, with no cause of death officially given. We will have to wait a bit to get the final, complete report and Dr. Stone's assessment.

More birds from David's camera as the migration begins to wind down

White-eyed Vireo

Canada Warbler

Chestnut-sided Warbler

Black-throated Green Warbler

Magnolia Warbler

Veery, 5/17/08


All photos taken on May 17, 2008 by David Speiser
And many more great photos to be seen on David's website:

http://www.lilibirds.com

Book News

Dear website readers,

Since many of you have been reading snippets of my book on this site for the last few years, I thought I'd copy the announcement of my June 17th talk at the American Museum of Natural History for those of you who aren't members. [The summer Calendar for members just went out.] June 17th is almost two weeks before the book's official publication date, but there WILL be copies of the book available at the event that evening. [It may be the first time I see the finished book myself. ] You can reserve tickets by phone--a number I've used in the past is 212-769-5200. Or on line, or just come on the day and get tickets then.

Central Park in the Dark with Marie Winn

• Tuesday, June 17
• 7:00 PM
• Followed by a nature walk
  Linder Theater, first floor
• $15 ($13.50 Members, students, senior citizens)

Explore the little-known world of Central Park’s nocturnal wildlife with naturalist Marie Winn, author of Red Tails in Love: Pale Male's Story. Learn about the bats, owls, raccoons, spiders, crickets, and slugs that become active in the park after dark. Learn where the daytime creatures spend the night. After an illustrated talk, Winn leads a guided walk to see some of these elusive creatures. Books will be available for signing.