Sunday, June 10, 2007

More From John Blakeman On Pale Male's Nest Spikes and the Wisconsin Report

Pale Male

And Lola.
From John Blakeman, who participated in early breeding trials of raptors-

I recall that you noted in previous years that the 927 birds would spend time thrusting their legs, "digging," as it were, during pre-laying nest preparation. But this apparently wasn't seen this year.

I'm wondering if the digging motions were prompted by the metal spikes the birds could feel beneath them. It's now clear that the prongs extended up into the egg-bearing layer. The hawks are powerful enough, I'm sure, to be able to bend the prongs over a bit.

Therefore, a photo of the nest in the fall, after the lining material has weathered away a bit, may show that the prongs in the center of the nest are bent over 45 degrees or more.

If this is so, the eggs still rested on the prongs, but instead of on the tiny tips, they rested on the bent-over sides of the prongs, exposing them to larger contact areas of heat-conducting metal.

Again, a telephoto of the nest from above, in November or December, after the lining material has weathered away to reveal the underlying prongs, would tell us the real story.

Again, the spikes need to be snipped off at their bases, or thoroughly smashed down flat.

--John Blakeman

It is possible that the birds did some digging in the bowl of the nest this season but as the sides are higher they might not have been seen doing it as they were previous seasons. Either way, Mr. Blakeman's recommendations are still very relevant to the current situation. D.B.

The Robin's nest I've been watching is becoming more full of nestlings and less full of eggs. Both Mom and Dad are now foraging for their meals. Look carefully at the rim of the nest and you can see the sheaths of the pin feathers beginning to "sprout" on the crowns of their heads.

Little Bit the Mourning Dove, Doorstep Dove and Friend's fledgling, was back in the garden sunbathing this afternoon, once again impersonating dirt.

Later in the day she appeared near the patio feeder and was helping herself to the seed on the ground when one of the Grey Squirrels ran past her. Something that a mature Mourning Dove wouldn't even notice, she watched warily. The squirrel taking the usual route to the feeder, then climbed the screen of the patio door. Little Bit craned her neck and watched him big eyed. Then when Squirrel took the next part of the route, leaping onto the hanging feeder, the momentum of which bangs the feeder into the glass door, Little Bit couldn't take it anymore. She gave two startled hops in two directions and then finally made it into the air. Wings whistling she fled for the Spruce trees. Squirrel, not to be deterred from his mission, then enjoyed a hearty meal of sunflower seeds.
Donegal Browne


Anonymous said...

Didn't John Blakeman say originally that the cold air under the cradle wouldn't be a problem as there was cold air under Red-tail nests in trees and the hawks didn't have problems?

Anonymous said...

Yes, John Blakeman (me) said that. And it's true for wild nest---which simply don't have multiple, internal heat-conducting metal wires connected to a metal screen exposed to the air.

It's not the air beneath the nest. It's the metal within the nest that conducts the heat to the exterior.


John A. Blakeman