Thursday, April 28, 2011

Fighting eyasses

Though the eyasses are still only a few days old, they are already starting to squabble and peck at each other. Here are the two oldest going at each other on Wednesday.

This can look pretty vicious, but John Blakeman gives us some useful perspective on the developmental need for such sibling fights.

"What you see is quite normal. With Red-tails, it’s never of any concern. No harm will come to any of the eyasses, unless the parents fail to bring sufficient food. If that occurs, a larger eyass can kill a smaller one, after profound hunger. That won’t happen here, by any means.

So, just as little kids “fight,” little eyasses do a bit of this. After all, these birds are born killers. All of what you see is normal nerve and muscle development. Just as with little children, the young eyasses have to learn how to use their muscles in coordination. Poking their beak at another sibling, even sometimes stealing a piece of food it is eating, is all normal and even helpful behavior.

Golden Eagle eyasses do this same thing. But universally, it turns out differently. It’s called the Cain and Abel Effect. Inevitably, the larger Golden Eagle eyass will slay the younger one. Golden Eagles most often lay two eggs, and both hatch. But the larger hatched eyass at some time before fledging will reach over and sink some talons into its brother or sister, killing it.

Our Red-tails are much more respectful and civil!

–John Blakeman

Wednesday, April 27, 2011

Furry mammal carnage at the nest

As the sun rose on the nest yesterday (Tuesday) we could see how productive the tiercel had been in bringing food to the nest. Carcasses of small, furry mammals - mostly baby rabbits and rats - littered the edge of the nest bowl.

Yesterday's newly hatched and bedraggled eyass #3 was now a fluffy, smaller version of its siblings.  All three look strong and active as the tiercel stands guard over their morning nap

Temperatures rose here yesterday into summer-like 80s, and instead of nestling down over the babies, the haggards stood by watchfully, lifting their wings slightly to stay cool.

When the formel settled closer, the eyasses stayed out in front of her, rather than under....

.... and soon collapsed into a sleeping pile.

As the afternoon heat intensified, we could see the haggards panting with their beaks open as they made sure the chicks were kept in the shade.

I asked John Blakeman - a master falconer and raptor biologist from Ohio who has consistently shared his enormous knowledge of hawks to help understand what we are witnessing at the nest - whether the heat would adversely affect the fragile eyasses.

John commented:

"The summer heat (in the 80s) is of absolutely no concern. Yes, the haggards are panting a bit, just like a hot pooch. This allows them to cool off. If they didn't have to be at the nest, they'd merely lift up a thousand feet or more and cool off in the cooler air aloft. But their focus is as it should be, at the nest, warm or not.

For the eyasses, the heat is wonderful. For their first 6 to 12 days out of the egg, they are poikilothermic, "cold blooded," unable to generate enough of their own body heat to stay warm. That accounts for the formel's brooding behaviors, keeping the eyasses warm under her breast feathers, when that is required. But with these warm temperatures, all is well. The three little ones are very comfortable out in the mid-day warmth.
It all looks very good for this year, with an fully-experienced pair and plenty of prey."
--John Blakeman

With an abundance of food in the nest, the Franklin hawk family is off to a fabulous start in their third year of raising chicks on the Board Room window-ledge.

Tuesday, April 26, 2011

And then there were three.....

At sunrise on Monday, April 25, as the formel grabbed breakfast, there were still two eyasses and one egg in the nest.

The tiercel was keeping the pantry full of supplies including a baby rabbit and another rat, all close at hand for the formel to feed herself and the chicks.

At 8:00 AM, the tiercel bounced in with yet another small furry mammal....

 .... which he proceeded to tear into.

Then followed one of those amazing moments which normally we would never see except for the privilege of the camera feed into the nest.
 The tiercel pulled off small pieces of meat, leaned forward and tenderly fed the formel as she sat on the chicks and egg.

She eventually stood up and moved closer to the increasingly red meal, and he continued to feed her as she stood beside him.

The egg remained in the middle of the action surrounded by the fluffy eyasses.  How could they have fit into their eggs less than 24 hours ago?  There now seemed to be small pip on the remaining egg, and sure enough....

 ...when the formel stood up in the early afternoon, chick #3 was on its way into the world.  Janette Benner captured these images of the hatch.

 Mom watched carefully as her third eyass emerged into the hot Philadelphia afternoon.

By about 3:30, the eyass was fully out of its shell.

The formel moved in to cover the chicks....

and pushed the empty shell farther away.

As she settled in, three small heads appeared.  The hatching was complete.

Soon, she stood up and began to eat.  The hatchling was still wet and bedraggled, and noticeably smaller than its siblings.  Their approximately 36 hour start will give them a size and strength advantage over #3 who will only get its share of food when the other two are sated.

As the formel fed, one of the eyasses was clearly interested and hungry, while the other one gazed up at the window.

Within a couple of minutes, both eyasses  focused in on their feasting parent...

... and crawled towards her over their newly hatched sibling.  She started to feed them....

... and soon #3 was completely tromped under its siblings!

 The formel settled back down on the now sated youngsters....

.... but it wasn't long before the tiercel arrived with fresh food - as if any more were needed!  Appeared to be another baby rabbit.....

Dad was intensely interested in whatever had happened in his absence, peering intently at the formel, willing her to get up, it seemed. 

But she would not oblige, so he stood patiently and waited.  In the close to 85 degree sun we had yesterday in Philadelphia, you can see the tiercel's open beak as he panted in the heat.  The two oldest eyasses also had their heads poked out from under their mother.

So, fast forward to this Tuesday morning, April 26, and early camera watchers saw all three eyasses active.  The tiercel brought in fresh breakfast supplies, and the formel fed the chicks.  Here she is settling down as the morning rush hour starts up in the city.

Monday, April 25, 2011

Eyasses' First Day

After the excitement of the first two eggs hatching, the formel sat quietly on the eyasses for a couple of hours.  When she finally stood up, we had our first glimpse of one of the chicks gazing out.

After inspecting her chicks, she dragged over one of the rat carcasses that the tiercel had brought to the nest....

.... and started to feed the eyasses.

The third egg sat right in the middle of the proceedings!

After she finished feeding the chicks, she had a rat snack herself.  We can rather graphically see the long tail and back legs of the rat lying on its back

The headless hawk!

There is also another dinner item on the rat's left.

The tiercel (dad) returned to the nest and formel flew off for a break from nest duties.  The tiercel is a  devoted father and settled in quickly over the eyasses.

When the formel returned, she wanted to get him up but he would not budge.  She headbutted him gently....

... then paced around while he studiously ignored her.

She finally was able to get him up and off the chicks.

She checked them out....

...then settled down on them.  At first, her wings are tightly furled against her back.

As she relaxes, her wings start to drop down to provide better coverage at the sides....

.... until she is fully relaxed.

It is always somewhat disconcerting when both haggards leave the nest unattended...

 ... but within a couple of minutes it is over and out for the eyasses as they sleep during their first Philadelphia afternoon.

Mom soon returns....

....settles in

.... and starts to preen her feathers.

By 4 PM, it's time to eat again, and the selection in the pantry is becoming more varied, thanks to the tiercel's excellent hunting skills.

Both chicks are strong and eager to eat, which they do voraciously.

These Easter Day chicks seem off to a great start.