Tuesday, March 15, 2005

WHEN DID THE REDTAIL INFLUX BEGIN?

WHEN DID THE REDTAIL INFLUX BEGIN?


On 3/15/05 I wrote to Peter Post, a highly accomplished birder who has been birdwatching in Central Park for more than fifty years:

Peter, I've been contending that as recently as 1991 [when Pale Male arrived in CP] red-tailed hawks were unusual visitors to Central Park . I'm not talking about flyovers, but birds staying in the park for some period of time. Am I right about this? Marie

Peter responded:
I agree with everything you say, except I cannot specify a year when Red-tails started to come down and actually perch in the park.

Peter

I sent this exchange to John Blakeman, with a note stating that I CAN specify 1990 or 1991 as a year when redtails were still rare. That is because Pale Male's arrival created such a great stir.. The appearance of a redtail in Central Park or anywhere else in NYC is pretty everyday now. Here is Blakeman's answer:

Marie,

Authoritative comments or data on the beginning of red-tail residencies in CP will be very, very useful. If this began in the late 80s, or early 90s, it fits very well with my anecdotal recollections of red-tail saturation of my countryside populations. Illegal shooting and trapping of red-tails declined dramatically in the 80s, as the arrest and citation records of state game authorities would reveal. By the 90s (and continuing today), there were simply no holes, no unoccupied habitats for large populations of maturing young red-tailed hawks. There was, and is, a severe "housing" (open habitat) shortage for red-tails. Tens of thousands of young red-tails are fledged in our respective areas each summer, but these birds simply have a hard time finding unoccupied territories with adequate prey populations. Those are owned and defended by old resident adults. In rural areas with markedly reduced prey populations (compared to the abundance of food animals in Central Park), red-tail territories are large, up to several square miles, and are strongly defended against invasion by young hawks.

If this scenario is an accurate characterization, and I think it is, then the incursion of red-tails into Central Park in the 80s and 90s begins to make a great deal of sense. The species is demonstrably able to adapt its hunting to the unique prey animals of Central Park. Pale Male began this urban colonization, and others have likewise learned to exploit the formerly untouched hawk resources of the Park. A wonderful story. I hope some accounts can be posted of early occurrences of red-tails in NYC.

Sincerely,

John A. Blakeman


Now that we're entering a peaceful month of incubation, there's time to return to some of the basic questions about the red-tailed hawk presence in Central Park. It has been suggested that the enormous amount of pigeon-feeding that occurs in the park, and thus the presence of great numbers of pigeons there is what served to attract redtails in the first place. John Blakeman responds:


Marie,


I'm not so certain that the pigeons by themselves were the only Pale Male prompt to get him to take up residence in Central Park. There have been a lot of human-fed pigeons in CP for decades, and not many red-tails. I still think our patriarch entered the Park because he could find no unoccupied territories in traditional rural habitats. But the plethora of pigeon surely didn't reduce his impulses to stay. A few hundred pigeons competing for a few pounds of scattered grain can quickly lose wariness in a crowd of other food-crazed birds.

And this raises a background question I've pondered. Is the real source of CP red-tail food actually from humans, from scattered bird food and horse-feeding grain? Could it be that the real, basal food resource for our hawks are humans themselves? Looks like it is.The Central Park food web or pyramid is quite different from anything out here in wilder, more rural areas.

How many pigeons would spend much time foraging in Central Park in the absence of human-provided grain? Without human-scattered food, I think the pigeons would be forced to fly across the river over into industrial areas and rail yards and work out a more mundane pigeon life eating natural weed seeds over there. Instead, the birds just fly around a corner or two, up a block or two, and drop down to quite artificial provisions of ample grain. But of course, the rock dove is artificial itself, not being a native species of the Western Hemisphere. Nature continues to evolve here.

Sincerely,

John A. Blakeman