Saturday, July 21, 2012

More From the Fabulous Fifth Avene Fledglings plus John Blakeman on Red-tail Vision

Photos and italicized commentary by our man in the field Jeff Johnson.  Un-italicized commentary is mine.

We're picking up from yesterday on the Fifth Avenue Fledglings with Flare on the Fourteenth of July.  Opera Star was perched in a tree taking his ease in his father's favorite stance when his sister appeared on the ground and began doing a little twig killing beneath him.

Opera Star leans over and gives her a look, possibly considering as fledglings do, a little surprise attack and tussle with a sibling perhaps? .

Fledge continues to play hunt all about the area under the trees. Metadata time 1828.
 Opera Star gives the "fledge look" to something off to the NNW. Metadata time 1829.
 Opera Star finally leaves his perch. Metadata time 1834.
 The two fledges we've been observing have flown into the NNE Cedar Hill trees. Metadata time 1835.
 Red-tail streaks in low-level diagonally across Cedar Hill from the SSE. Metadata time 1836.
 Fledges watch this very closely. Metadata time 1837.
 Red-tail continues this low-level airshow as fledges watch. It must be a parent, but I can't tell which one or if anything is being carried. Metadata time 1838.

Interestingly the tail on the above hawk appears brown in the photograph but sometimes modern cameras "make decisions" about the fact that the rest of the body is a certain color and if tail color isn't clear  they "make it match". 

It was a food drop and one of the fledges has something mantled in a lower tree limb at the top of Cedar Hill without my having gotten any frames of the actual drop (once more !).  Metadata time 1839.

Don't feel too bad Jeff, I've been taking pictures of Red-tails in breeding season since 1995 and I've yet to get "the shot" of a drop either. 
 Fledge begins eating. Metadata time 1839.

 This fledge watches the other have dinner from a tree seventy feet to the west. Metadata time 1840.

 Mantled fledge eating seen from ENE. Metadata time 1841.
 Less guarded now, the fledge continues to eat (seen from west). Metadata time 1844.
 927 Nest check from near the Sailboat Pond. No one visible. Metadata time 1851.

Remember when Opera Star when Opera Star leaned his head in one of Jeff's photographs and I said that, Red-tail expert John Blakeman originally explained what was going when Charlotte, mate of Pale Male Jr.  did the same repeatedly while sitting the nest on the Trump Parc?

I asked for an encore of  his explanation and he, as always a major help in these matters, sent it along spritely.


I haven't seen Jeff's photo of an immature looking up into the sky, but the only reason this is done is to observe a bird above; usually some hawk or other raptor.
In the hot weather of late, RTs and other hawks can ascend on a thermal (many miles away) and be at 5 to 10 thousand feet in a few minutes. It's never 95 degrees at those altitudes, and RTs can simply lock their wings and soar effortlessly (and cooly) up there for hours, unseen by virtually anyone on the ground, except for another Red-tail.
Red-tails will peer up at other raptors soaring above, particularly peregrines. They pay little attention to Cooper's hawks or kestrels up there.
Often the Red-tails will be seen looking above with their heads tilted to the side, as though they were looking out of the side of their heads, with one eye, not straight forward. That's because hawks have two foveas in each eye, areas of highly concentrated light-receptor cells. We humans, and most animals, have a single fovea right at the back of the eye, allowing us to see in detail in the central area of vision straight ahead. But the most concentrated light-receptor cells in the retina of a hawk is not at the back of the eye, but on the side. So, when a Red-tail is seen apparently looking out to the side, but with one eye angled up into the sky, it's looking at something in the great distance, using but one eye, with the image focused solely on the secondary (but more detailed) fovea.
People unfamiliar with this are easily confused about what a hawk is looking at when the head is tilted to the side, with one eye angled into the sky. Makes no sense to those of us who can use only the foveas at the direct rear of our eyes.
I have some fun watching this in my falconry Red-tail in October here along the south shore of Lake Erie in Ohio. Lake Erie is wide, so migrating Red-tails and other large hawks elect to skirt around the western end of Lake Erie, between Detroit and Toledo, instead of trying to fly 50 miles or so across the water. So, all of the migrating raptors going south out of the counties of Ontario on the north shore of Lake Erie get concentrated as they fly around the western shore of the lake.
Once they get past Lake Erie, they simply head straight south, pretty much following I-75. So, I've often had my falconry Red-tail on my fist, beneath this stream of hawks passing overhead. In a quick scan of the sky I can see nothing but blue (or gray -- more likely) sky. But my hawk is tilting her head right and left, keeping track of the migratory hawk traffic above.
I've learned where she's looking when she tilts her head, so I can point my binoculars right where she's looking. And, sure enough, there will be a hawk or two in that field of vision.
Quintessentially, Red-tails are visual creatures, facilitated by not one but two retinal areas of intense light-receptive cells.
--John Blakeman
Happy Hawking!
Donegal Browne 

Friday, July 20, 2012

Pale Male and Zena's Fledglings Go For It and the Bronx Goes For the World's Biggest Rooftop Farm

 (In case you've not heard yet.)

  Fledgling photos and italicized commentary by Jeff Johnson, the un-italisized commentary is mine.
 After a quiet day on the 13th, Jeff Johnson, our fledgling finder on the ground, had a dam buster of sightings on the 14th! 
I was able to spend about three and half hours with the Red-tails and got better frames than Friday. Got into the Park at mid afternoon and entered from the MET grounds at 79th and 5th Avenue. I wasn't hearing any Red-tail sounds and was was surprised to walk up on a fledge sitting on a low limb in a tree at the north end of Cedar Hill. It's at top center frame because CS6 will sometimes give me an odd crop when lens profiling the RAW file. Metadata time 1608.
Second fledge arrives in the tree tops to the left on Cedar Hill. Metadata time 1610. 

 Initial fledgling spotted as seen from the base of its perch (camera facing west). Metadata time 1612.
 Fledge first spotted shifts to a Pine about forty feet SSE. on the hilltop. Metadata time 1618.

This fledgling just reminded me that Red-tails have a special function in their eyes for looking straight up.  Ohio Red-tail expert, John Blakeman, can explain it very well which he did back in 1995 when we were watching Pale Male Jr. and Charlotte's nest on the Trump Parc.  I've an email out to him in hopes he'll do just that for us.
It's joined almost immediately by a second fledge. Metadata time 1620.
Both fledglings begin looking WSW. Scanning in this area I see no activity such as a parent soaring or perched nearby. Metadata time 1621.

But I'm betting they've got an eye on a parent over there.  Oh to have the eyes of a hawk!

Third fledgling swoops into the treetops on the middle slope of east Cedar Hill. Metadata time 1626.
 Pale Male is on his favored Oreo building antenna perch. Metadata time 1628.
My favorite fledge which I think of as the Opera Star, has moved into a tree roughly at the center of Cedar Hill just north and to the left of Glade Arch below. Metadata time 1630.

And I note that Opera Star has taken up his father's (and the late Tristan's, who some would say was his half brother) signature foot tuck.
 Opera Star is joined by a second fledgling. Opera Star looks slightly smaller than the other fledge to me. It's why I call Opera Star a male and the other two equally sized fledges as females. Veteran Hawk Watchers caution that all three look too close in size right now to be making such assumptions. Metadata time 1635.

I too think that Opera Star is a male. (Note that is stated as an opinion not a fact.) Males have a different shaped head than females. (This is a fact not an opinion.) 

I'm not the never-known-to-be-wrong Jemima Parry-Jones but compare the head shape of the fledgling above, (up one photo) to the fledgling below.  The one below, looks "hawkier" as hawkwatching photographer Francois Portmann would say.

 Second fledgling doesn't stay and moves to another tree lower on the hill. Metadata time 1637.
 Now Opera Star gets restless and launches. Metadata time 1641.

 Could he be jockeying for position for and upcoming food delivery?
 But only moves to an adjacent branch. Metadata time 1641.
 Opera Star scene. There has been very little vocalization from anyone during all the movement. Metadata time 1653.
Still quiet Opera Star fledge. Peers out to the NE quadrant. Metadata time 1653.

 Up comes that foot again.
Opera Star preens. Metadata time 1701
Red-tail soars 12 o'clock extremely high and because the Oreo antenna is now empty I wonder if this is Pale Male hunting. I've lost track of the other fledges, but Opera Star isn't excited nor do I hear any fledges begging. Veteran Hawk Watchers have said Pale Male is still the sole provider of meals, though all three fledges have been observed as having caught their own meals. All the fledges seem to be very capable fliers too, with one having even been observed at high altitude in the company of Pale Male learning to hunt. Metadata time 1706.
Fledge alights into the treetops NNE Cedar Hill. Still no begging going on. Metadata time 1710.
Opera Star, still in his same tree becomes entertains the idea of a squirrel dinner. Metadata time 1711.

Is the squirrel smiling perchance?
Maybe just wait for a delivery…it's too hot to move. Metadata time 1711.
 Squirrel continues on down the tree. Metadata time 1711.
Squirrel seems offended that Opera Star didn't make an attempt. Such a spoiled child, waiting for papa to deliver!!! Metadata time 1711.
 Fledge to the NNE still in treetop and pretty much quiet. Metadata time 1713.
Opera Star still tracking the squirrel, so he isn't totally uninterested in getting his own dinner. Just lazy. Metadata time 1714.

Now, now, no casting dispersions on Opera Star's work ethic. 
  Perhaps instead of being lazy he's learned, as all successful Red-tails do,  that a single hawk can't successfully nab a squirrel in a tree.  Therefore there is no reason to waste the calories chasing it.  Instead,  if Opera Star displays little interest in him, squirrel might get foolhardy and make a dash across the lawn where Opera Star could conceivably grab him.

Opera Star looking due north. Metadata time 1716.

Fledge in NNE treetops begins begging. Metadata time 1718.
Opera Star preens and rests leg and stays silent. Metadata time 1728.
Sporadic begging sounds from other fledglings heard but Opera Star just preens.  Metadata time 1738.

Opera Star now fires up his pipes and does some begging while looking NNE. Metadata time 1742.
Opera Star goes back to some preening. Metadata time 1753.
 Another fledge lands in a tree to my right which is WSW about fifty feet away. Metadata time 1756.
 Opera Star gets very excited about something and it looks almost like he's in a semi mantled pose, though he could be just in a wings transition from preening. Metadata time 1804.

Perhaps thinking about making a controlled with wings leap down?
 It's a squirrel again. Probably a different one. Metadata time 1805.

I agree this squirrel doesn't appear nearly as cocksure as the previous one.
Opera Star shifts branches this time in pursuit. Metadata time 1805
Moving along with squirrel. Metadata time 17o5.
Squirrel skitters away leaving Opera Star upset. Metadata time 1806.
Opera Star has pivoted from his predominantly NE quadrant scanning to being interested in something ground based right below. Metadata time 1825.
It's a pair of maturing puppies  (shown in combined frame) being walked that has his attention. Metadata time 1825.

It is interesting that deeply human habituated hawks tend to go about their business in the presence of humans but any business near the ground  tends to grind to a halt if there are dogs in the immediate area.  I've always suspected that they know dogs aren't all that trustworthy, when it comes to wildlife, and give them a wide berth.  

Note that Opera Singer is giving the dogs a good bit more of attention than he'd likely give an unknown human if he were without the dogs.
Fledge swoops onto grass under the trees to my right {WSW about fifty feet). It's probably the same fledge which landed in the tree there earlier. I lost track of what it was doing while I was engaged with Opera Star. Metadata time 1826.
Fledge begins hunting twigs. Veteran Hawk Watchers say that they are a little surprised that such play hunting is still being done now that all three seem capable of actually hunting real prey. Metadata time 1826.

I haven't found twig hunting all that unusual anytime in a young hawks first year. Certainly the don't seem to do it nearly as often as when they are these current fledglings age but I observed a Brown-tail "hunting twigs" in the February following his first winter.  I'd seen him about a half hour previously sitting in a tree looking unfocussed and  not at all energized.  When I was returning on the same path, suddenly he leapt off his perch, killed a twig large enough to be considered a branch, and appeared much more energized and well, "happy" in a hawk way.  It was as if he'd used the game to cheer himself up.

I wondered at the time that it being Spring he might be having urges, which would translate into wooing a formel one day but he wasn't sure what to do with them quite yet in his life so resorted to a fledgling form of play to help satisfy his "craving".  
Opera Star watches his sibling play hunt.  Metadata time 1827.

As Blogger has decided he is tired so he's being cranky, you'll have to wait until the next post to find out if Opera Star actually does decide to leap down on his sister's head-- 

But first,  just in from contributor Diane D'Arcy, the Bronx is doing it again,  only this time in a much much bigger way!

According to the website DNAinfo the Bronx may soon be the home of the world's largest rooftop farm:

Don't know that this would help the birds but it sure would cut down on the heat generated by that huge roof shown in the photo.

Best, Diane

As non-raptor city birds are always on the look out for a little greenery for their digestion, I can see this place becoming quite an interesting hunting ground for city raptors.

Happy Hawking 
Donegal Browne