Sunday, April 04, 2010

Athena and Atlas' Eggs, Atlas Gets a New Mate, John Blakeman, and New RTH Pair Discovered.

Photo by Peter Richter,

In regards to Atlas and Athena's eggs--

The eggs were retrieved and put into an incubator. Though it is a long shot that they will hatch as Athena went missing early in the morning on Wednesday and the eggs were not retrieved for some days. Atlas would have sat on them to some extent but having no mate he would have had to hunt for himself in order to eat during that time and the eggs may well have cooled enough to loose viability. Keep your fingers crossed.

If there is a hatch it will occur sometime around April 24th. There are non-releasable foster mother hawks who would then raise the eyasses so no human imprinting would take place and when they were ready they would be placed with wild parents who had eyasses of about the same age so they could be trained in the ways of wild hawks.

Yesterday Jules Corkery, a main watcher of Atlas and Athena for years, reported a second Red-tail had appeared in Atlas and Athena's territory. There was some screaming on Atlas' part so it wasn't clear if the "visitor" was another hawk hoping to gain territory or a female hoping to nab Atlas as a mate.

The biological imperative wins---

It is good news, Peter Richter , , reports that he observed Atlas and his new mate copulating and working on the current nest. More photos of the new mate, B, I believe her name will start with B as Jules Corkery is working on an alphabet system but perhaps her alphabet system works differently from how I think it works. We'll see.

With the eggs missing from the nest there is every chance that Atlas will double clutch as Charlotte and Pale Male Jr. did the year their eggs were blown from the nest. Though the hatch of course was later than normal everything worked out very well. The eyasses fledged successfully and were well trained to hunt for themselves by the time they needed to do so.

Also on Peter's site, link above, you can see photos of the newly discovered hawk pair's "unusual" nest site. Actually it reminds me a little of the Tulsa nests, except the height of course.

I just noticed that there are some missives from Red-tail expert John Blakeman in my box. Let's see what he has to say.

THE BATH AND THE FIGHT from John Blakeman

Two items.

I find the photo of the haggard red-tail emerging from a dip in the East River very interesting. Red-tails often bathe, sometimes even in colder weather. But I'm surprised that the bird elected to bathe in saltwater. I presume that the East River at this location is essentially sea water, with a typical seawater salt concentration. If the river here is mostly freshwater, my comments should be discarded. But if it's saltwater, this is very interesting.

I don't think hawks handle dietary salt very well. Of course, there is normal salt concentrations in the food they eat. But I've just never heard of a red-tail bathing in saltwater. These birds very often take a drink when bathing, and I'm not certain what a mouthful of East River saline might do for the bird. Of course, she knows what she's doing, and if she had any aversion to saltwater, she'd take that into account and probably not swallow any.

But perhaps a bigger question might be the deposition of salt crystals or dust on and under her feathers when the saltwater dried. I'm wondering how this might affect the feathers and the oil that repels water. Most likely, it has no detrimental effects. But in summary, red-tailed hawks are just not much regarded as a maritime bird. How much of a real maritime salty might this individual be?

All of that is pretty thin speculation. The following is not.

The physical combat between the two rural Wisconsin red-tails is very interesting, and very explainable. There are two possible explanations.

The first would be that these are merely two adjacent haggards defending — here rather physically — a contested or yet-unresolved territorial border. Each thinks it's in its own territory, and the other an uninvited intruder. The definitive photo is the one with the perched hawk bowing to the other. To us, this might look to be very proper, but we are not hawks, and they don't follow the conventions or decorum of human diplomacy.

In fact, the deep bowing is an intraspecific threat display, a body posture that only red-tails (and, dare I say, competent raptor biologists) understand. This bowing posture, in red-tail diplomacy, is a decided "Get your tail feathers right out of here, right now. This is MY territory, and you should know that!"

But the other bird disagreed. It was willing to challenge the first hawk and stand its ground (well, it's utility pole). The resultant gyrations and physical challenges in the aerial flights were the next step. Although the crashing of one bird into another looked pretty violent, it really wasn't. No doubt, the attacking bird did give the other a good aerial punch. But it didn't, and wouldn't, necessarily grab it and sink talons into the defending bird's flesh.

At some point, probably toward the end of your photos, one bird will back off and give subtle signs of retreat. The matter will then, at least for a while, become resolved.

The second explanation for all of this might be (I hope not) that a resident pair has lost a haggard, that a resident hawk has died, and as happens so frequently in cases like this, a "floater," an un-attached new adult has instantly come in and assumed the position of the deceased bird.

But the new bird, until now, has not yet learned the formerly agreed-upon territorial barriers, thereby instigating the observed challenges. If this were the case, the new replacement adult will get the message and learn how property is divided by the adjacent pairs in that neighborhood.

This sequence of photos illustrates how red-tails sometimes resolve territorial issues. Usually, far more ritualistic and less violent flight displays and challenges determine all of this in January and February. For some reason, one of the birds hadn't come to a proper understanding of the border, so a confrontation ensued.

But both birds survived with no injuries, only some bruised egos. Life will go on with greater restraint now.

I've seen all of this up close — and too personal. It's one of the things falconers must be attentive to when we take our trained red-tails into new areas to hunt. If we and our birds happen to start walking through a prime hunting area of a resident hawk, it will very seriously challenge the falconer's red-tail, especially when it's flying free, off the fist of the falconer.

I did this one time, entering into a field with my very trusted and experienced adult falconry red-tail. I tossed her off to allow her to hunt from a tree perch, as I scampered about trying to kick up a rabbit for her. But very quickly a resident red-tail came shooting through the sky to challenge my interloping bird, Savanna II.

When the old haggard started flying at Savanna, she knew instantly that I had placed her in somebody else's living room, without being invited in. Long before the resident bird could get near Savanna, my hawk was on the wing, high-tailing it away from the resident bird. I had to go some distance to retrieve Savanna, after she exited the challenging bird's hunting area. Savanna was glad to come down to the piece of meat on my fist and allow me to protect her from the incensed local bird. There was no physical contact, but the tenseness was evident. I took Savanna back home and gave her an over-sized meal of fresh rabbit flesh from a previous kill. She was happy, and that resolved the matter.

–John Blakeman

I don't know the status of the salinity of the East River. I'm trying to remember if I've seen anyone drink out of it.

You're right now that you mention it, the fight looked awfully violent, and then there was all that screaming which added to the intensity, but nobody seemed to be dripping blood nor did anyone seem to become disabled in any way.

The only instance of bowing I've seen in NYC was the day, that a dope of an immature Red-tail flew over and perched on the roof of 927 right above the nest with Pale Male and Lola both on it. Pale Male immediately flew up landed about a foot from the visitor and went into that offensive bowing position. The visitor looked deeply shocked and took off like a shot. Pale didn't even bother to follow him.

Poor Savannah II, that must have been rather disconcerting. I take it that rapid flight is the appropriate response to show you aren't making some kind of challenge to the resident bird. Then you go to "Dad" once that point is clear. Speaking of which, what is the relationship in bird terms between a falconer and the hawk?

Donegal Browne

1 comment:

Your man in NYC: Bill said...

Regarding the salinity of the “East River”: It is not a river at all. It’s a waterway that connects the Atlantic Ocean (by way of New York Harbor) with Long Island Sound. It separates two islands: Manhattan Island and Long Island (home of the 2 largest boroughs of New York City… Brooklyn and Queens) and is an estuary, or to be technically accurate, a strait. The Hudson River is an estuary also, but becomes an actual river just north of the George Washington Bridge. South of the bridge, the Hudson flows between the mainland (New Jersey) and an island (Manhattan) and then flows into New York Harbor. The East River is third highest in salinity (average 23ppt) in the New York area. It is lower than the Harbor (25ppt) and the Sound (28ppt), but higher than the Hudson (18-20ppt). The Hudson is fed by freshwater from upstate (if that can be called fresh) and mixes with the Harbor which in turn is fed by the Hackensack and Passaic Rivers in New Jersey. The East River gets a little freshwater from those sources and from the Harlem River which connects with the Hudson. But mostly, the East River is fed by Long Island Sound (which itself gets a little freshwater from rivers in Connecticut and Long Island) and the Ocean. Confused? Take two aspirin and call us in the morning. The picture of Athena bathing in the river was most likely taken up by her home on the Triborough Bridge (now called the Robert F. Kennedy Bridge). At that point, a little freshwater from the Harlem River may have made the water more attractive. At any rate, when you need a bath, you need a bath and that’s the only water around.