Thursday, April 19, 2007

Blakeman responds- and quick local Hawk Report

Pale Male and Lola on the nest - April 19, 2007
photo: http://www.palemale.com


Last year's nest at the Cathedral Church of St. John the Divine
Photo by Bruce Yolton Http://www.urbanhawks.blogs.com


Junior and Charlotte's new nest at 888 7th Avenue
Photo: Bruce Yolton


Marie,

I appreciate Ben Cacace's comments on my posting on the Queens red-tails corner-crash ambush method of taking perched pigeons. Jeffery Kollbrunner just emailed me and said that he has been observing this capture method for twelve years, so it's not incidental or isolated. And he mentioned that he just recently observed a member of a different pair of local red-tails take a pigeon by the same method.

But I'm certain that it's not the only method of pigeon capture. And I have no idea if it's frequently used by the Central Park red-tails. You mentioned seeing a red-tail snatch a pigeon from a flying flock, a feat that seems quite remarkable, given the speed with which pigeons can fly and their ability to maneuver away from pursuing raptors. Peregrines themselves often fail to take pigeons from flying flocks. But I'm certain what you saw happened, that the red-tail somehow took a pigeon from the flock aloft. Was the particular bird taken at the back of the flock, flying with a bit less vigor, or with the slightest handicap? No matter, the capture shows the remarkable new skills of the urban red-tail.

It might be perceived from my recent note that I thought that the around-the-corner-at-speed method was the primary pigeon hunting method of all urban red-tails. Certainly that's not the case, as you and Ben have described other methods. And Jeffery Kollbrunner stated that he's seen low-angle strafing attacks that succeeded.
And of course, red-tails are going to also opportunistically pluck squabs from pigeon nests at will. That would be an instinctive, unrehearsed natural technique any red-tail would resort to upon discovering a plump baby pigeon or two on a building ledge.

Consequently, urban pigeons are being taken profusely by resident red-tailed hawks by a number different methods, ones that I can assure readers seldom or never occur in rural, wild populations (except for nest raids).

My main contention, that red-tails are exceptionally intelligent and adaptive in their hunting techniques stands. I made no mention of their taking of urban mammals such as rats, mice, and squirrels, as these methods surely do not differ from the ones my rural hawks use.

Secondly, the availability of abundant prey controls reproduction (number of eggs and eyasses) and is a central issue in urban red-tail biology. Just how those prey are captured (by multiple methods, many new in urban areas) is a question that needs to be answered more fully. I believe this discussion might prompt urban hawkwatchers to be more attentive and note how the pigeons are being taken. When we understand that fully, we will then understand how the species succeeds so well in its new, urban environment.

And I hope that I didn't convey the thought that red-tails never drink water. They surely do, as Ben has observed. But unlike Cooper's hawks and other accipiters, red-tails do not require daily baths or drinking water. Some red-tails drink and bathe frequently, others seldom or never do. The availability of bathing and drinking water is by no means a requirement for the residency of a pair of red-tails. It is for Cooper's hawks.

Good discussion. Good to hear from people on-site, with first-hand local observations. Until the last 15 years or so, red-tails virtually never lived in cities, never took urban pigeons, and seldom raised young there. As I stated sometime ago, this is all very new red-tailed hawk biology that needs to be documented. Wonderfully, the red-tail is no longer just a country bird -- and in the city it doesn't hunt or feed like it does in the countryside. There aren't any voles in Central Park, the primary prey of rural hawks. But out here, we don't have any vulnerable pigeons, either.

Everyone, please post observed prey captures. I doubt that anyone has the complete picture yet.

--John Blakeman


Local Hawk Report as of 4/20/07

1. Pale Male and Lola:
Still sitting. Eggs should hatch in the next 5 days.

2.Central Park South Hawks [Junior and Charlotte:
Still sitting at their new 7th Avenue nest.

3 Cathedral Hawks:
Still sitting.