Coopers Hawk (accipiter cooperri)

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Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Mar 27, 2018 4:37 pm

This thread is for discussion of the Coopers hawk (accipiter cooperri). Previous thread from the old forum here:

http://archive.hancockwildlife.org/foru ... pic=347126

https://www.allaboutbirds.org/guide/coo ... ifehistory

Image

The Coopers hawk is one of the three accipiter species of hawk in North America, and have become a common urban hawk in a number of areas.

ostrich
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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Mar 27, 2018 4:58 pm

Mar 27:

Over the past couple of weeks my local Silverthorn Park Coopers have been continuing activity, up until today I had observed vocalizations and interactions early in the morning several times, including mating a couple of times, but without any obvious stick work at all within the park. However this morning I saw the male flying several sticks up to last year's nest, followed by mating with the female. So this is the first definite indication of activity that suggests they intend to reuse that nest. There are other trees which might be possibilities for a nest, but not very many others left, so this is the most likely option.

As of Mar 18, the High Park Coopers were also in the midst of nest building and courtship activity - this time they seemed to be centered again on last year's nest, although there is a small nest structure in a nearby deciduous tree. But the female flew up into last year's nest bowl several times, so they also seem to be likely moving towards using last year's nest.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Apr 08, 2018 6:59 pm

The last two weeks I have visited (Apr 1, Apr 8) I have seen the High Park Coopers showing early morning activity with some signs of nest work both in last year's nest tree, and the older one from the year before.

Apr 1 - both adults were in the vicinity of last year's nest, with mating, the female seemed to fly up into the nest on a couple of occasions, with possibly some sticks flown in. However subsequent to this, both adults ended up wandering up closer to the old nest area. The female actually seemed to fly rather aggressively at a squirrel which was in an adjacent tree which was surprising as they don't seem to notice them most of the time.

Apr 8 - this morning (~6:45am) I found both adults nearby the old nest area, with definite work being done on it. The female several times flew up into the nest bowl and made quite loud kek vocalizations on a couple of occasions. However the male remained roosting nearby and didn't bring any sticks to this nest that I noticed. However about 10 minutes later the male did start flying around to different tree branches and twisting them (this is usually a sign they are trying to find one they can successfully break off), when he finally did so he flew off in the opposite direction towards last year's tree. Both were briefly roosting together near the tree when I located them again, but did not mate. But the female shortly returned to an area closer to the older tree and was making vocalizations again.

This seems to give the impression that the female is set on using the older nest tree, but the male is perhaps still trying to present last year's tree as an acceptable option. However the female makes the decision on which nest location to use, so based on this it seems more likely they may switch back to the older nest.

In my territory, both adults have been present in the last couple of mornings, and the last two days (Apr 7, Apr 8) I have noticed the female still present in the park much later in the morning (around noon both times), this is generally an indication that she is getting closer to egg laying, she will tend to spend more time in the nest area each day, and testing out the bowl prior to the first egg being laid. However based on last year it should still be a couple of weeks before the first egg.

Image

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Wed Apr 11, 2018 9:29 am

Apr 9 - I was quite surprised to see my local female roosting in the nest tree just close to the bowl late in the afternoon on Monday, around 4:30pm when I was going out. Then it was evident that the male was there too, as he left the tree and flew over my head off to the SW as I was coming around to take a look. It's conceivable he was there having made a recent food delivery, the female presence is interesting because increasing presence in and around the nest tree over later and later periods in the day is something I take as an indication that egg laying is approaching. I was a bit surprised to see here there this late in the day this early in April.

There was also a TOC meeting at High Park with a walk through part of the park prior, during this both High Park adults were spotted close to the older nest spot, just across the path, the male appeared to have just delivered a food item that the female had in her talons and was flying to a perch with.

Apr 10 - in the morning I sighted both of my adults roosting side by side in a branch a little ways away from the nest tree. I did not see food but normally the male is around after he's provided some.

Apr 17 - after two days of that awful ice and sleet filled weather, I was able to confirm that the nest still looks in good shape and I spotted the female roosting in one of her nearby spots this morning. There's still a lot of ice on the ground which makes it hard to walk around in the park.

Apr 19 - early in the morning around 8am I found that the female was up in the nest bowl, not sitting flat, but somewhat crouched in the bowl, she seemed to be quite intent on staying there quite still. I was able to observe her for a few minutes and also found her again in the nest late in the day around 6pm. This is usually another sign of impending egg laying, as she'll start to spend periods in and around the bowl in the days prior to laying. I don't believe there was any sign she has done so though.

Apr 20 - today I checked the nest tree a couple of times in the morning and the early evening around 6:30pm, but didn't find her in the nest on either occasion. In the latter case I was able to see her roosting in one of her usual spots across from the nest.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue May 01, 2018 8:25 pm

Apr 22 - I visited the High Park territory and was not able to discern any activity around the older nest, contrary to what I was expecting, but there was some extremely agitated chickadee calls close to last year's nest, and it wasn't long before the female did fly in from somewhere nearby into last year's nest. She flew back out a couple of times, but then ended up standing in the nest bowl and was there for at least a half hour, which seems a pretty strong indication that she's back to intending to use that nest.

Image

I did also manage to find the male a bit after that nearby, he had a very large crop, so I wouldn't be surprised given how agitated the chickadees were, that he might have caught one of them.

Image

Apr 29 - I visited the nest area again for a while but didn't succeed to definitively spot the female in the nest or a sign of activity there. Once again I did see the male roosting nearby - if she's sitting yet it will take further checks to spot her.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue May 01, 2018 8:26 pm

I am putting down Apr 26 as the likely date for start of incubation for my territory - I've been seeing the female consistently on the nest in sitting position since then.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Fri Jun 01, 2018 8:04 am

For the past several days now, back to May 27-28, I've been keeping a close watch out for any definitive evidence of hatching (normally food being brought back to the nest and clear attempts to feed are the best indicators), without catching any yet. From about May 27 I have been seeing the common indicators of the female seeming to sit somewhat higher in the nest, this can happen somewhat in advance of any hatching, but seems to typically start a handful of days before.

I have seen at least two different occasions on May 29/May 30 when I did catch the male in the area, either present when I went out or making announcement call. May 29 occasion he did appear to have some food which he continued to pull at and perhaps partially eat for about 7-8min on his own. The female finally flew over and displaced him off his perch, but it was hard to tell whether any food was transferred to the female, they both ended up moving further away behind some of the intervening trees. When the female eventually returned to the nest I didn't see any clear sign she was doing any feeding.

Yesterday (May 31) I spotted the male on one of his typical perches nearby the nest, the female did come over but flew into branches above him and a tree over, and there was no food exchange (although there may have been earlier since male seemed to have a visible crop and female may have as well). A bit oddly the female flew back and forth to the nest a couple of times grabbing a couple of very tiny twigs and stuck those in the nest.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Jun 05, 2018 6:33 pm

June 2-3, on both days I did catch either arrivals by the male which clearly included food, or went out when both adults were present, with the male attending the nest and the female with food nearby that must have been recently delivered. On each of these occasions though I failed to see any of the food brought to the nest, and the female appeared to finish consuming the food before later returning to the nest and displacing the male.

June 4 - during early evening, I was able to hear the male making an announcement call indicative of an arrival, and upon walking over to check their usual nearby branches for exchange, the female had yet another delivery. This is the first time I did see a clear retrieval of the food and the female carrying it to the nest, with definite indicators of her standing on the rim and pulling pieces off and offering them into the bowl. As typical very early after a hatch, it was not possible to make out any chicks from the ground, but this should be a reliable indicator that there has been at least one hatch.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Jun 10, 2018 6:27 pm

For most of the last week I had not had many opportunities to try to check the nest, however

June 9 - in the early evening I was able to catch a feeding in progress and for the first time I was able to just barely see some white moving just in the gaps between the sticks at the edge, of a chick in primary down. It was impossible to tell however, whether there was more than one.

June 10 - again an early evening food delivery resulted in a feeding, and from the grass side I could see a little better this time some movement of a hawklet during the feeding. I then walked around to the sidewalk and looked from that side, and I was able to get a much clearer view of at least one head in the nest. Again though it was tough to tell how many might be in there, a head kept bobbing up and down but it was never possible to see more than one at any given time.

I was also able to confirm at least one hatching at the High Park nest, June 9 I spent about an hour and a half waiting near the nest area hoping for a food delivery which would give an indicator, without luck. However today when I went to the nest area mid-morning when I arrived the female was standing on the nest edge and a feeding was in progress. It was definitely not possible to make out any hawklets in the nest given the nest is so high from the ground, but the female was pulling pieces of food and offering them into the bowl.

https://www.youtube.com/watch?v=Z7Cr5sPD54o

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sat Jun 16, 2018 2:09 pm

June 11: I observed the High Park female again standing as well as brooding in the nest, but otherwise hawklets are still not visible from the ground.

June 12: I was able to observe from the ground another feeding in which there was a clearer look at what was nearly certain to be two separate heads in the nest, although in binoculars there wasn't quite a 100% clear view of two heads at a time.

June 14: I recorded a morning feeding in which there was finally an unambiguous view of two hawklets. I could not see any clear indication of a third hawklet in the footage, but the hawklets were not sitting up high enough to tell for sure whether there could be more than two or not. The hawklets still appear to be in full white primary down, without any significant feather development yet.

https://www.youtube.com/watch?v=BKiP_dLEhts

June 16: This afternoon I again saw two hawklets during a feeding, this time both individuals were sitting up noticeably higher and were more visible, although not standing yet at this point. But short stretches of the legs and accompanying opening of the wings were visible.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Jun 24, 2018 5:02 pm

Development of the hawklets has been continuing steadily, and on repeated days during multiple checks to the nest I've caught two or three feedings in a day, which suggests again that these hawklets are being particularly well fed. In previous years it's seemed to have been more infrequent to actually catch a feeding.

June 14 - some additional footage https://www.youtube.com/watch?v=Xsrnfc9SPC8

June 17 - this caught a feeding which still is only showing an obvious indication of two hawklets in the nest. There as yet has still not been any strong indication of a third. The hawklets are still in white down, but the start of pin feathers is

https://www.youtube.com/watch?v=TXIr7ZaKR1w

June 22 - I did not catch a feeding on this occasion, but again the continuing pin feather development on the visible hawklets can be seen.

https://www.youtube.com/watch?v=9xgys7JgREk

From the ground, June 22:

Hawklets in the nest;

Image

Emerging pins visible:

Image

Female and hawklet:

Image

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Jun 24, 2018 5:05 pm

Adults from June 22;

Male:

Image

Female:

Image

June 23: I also observed a hawklet standing up in the High Park nest, it was difficult to get views for long because of rainy weather, but it confirms there are certainly hawklets in the nest. The development looked similar, with the bird still fully in white down with some indications of feather development, perhaps a bit older since it seemed stronger on its legs and able to stand more easily.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu Jun 28, 2018 6:09 pm

June 25: I was able to catch another good feeding, with both hawklets will visible in the nest, both have definitely lost significant amounts of their down on the body and full feathering is coming in quickly.

https://www.youtube.com/watch?v=NJKD5dNe97o

Image

Image

ostrich
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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Jul 03, 2018 3:47 pm

June 30: Lots of very exciting observations from High Park - I visited the nest in the morning and was very quickly rewarded with a sight of several hawklets in the nest.

Image

About 20 min after I arrived I was fortunate enough to catch a food delivery by the female which was a good opportunity to try to confirm numbers in the nest. Video footage definitely confirmed 5 hawklets, which is interesting, since it is larger than the previous two years (4 each). I am happy I caught this footage when I did, as the footage also shows they've become very active and are really starting to branch. Very likely in no more than a few days it could become hard to see or document them all together.

https://www.youtube.com/watch?v=DUzvr7-Xpw8

https://www.youtube.com/watch?v=m03DUhw7otc

https://www.youtube.com/watch?v=-_xEd-aAvJ4

ostrich
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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Jul 03, 2018 3:55 pm

July 2: In my own territory, I was also able in the morning to confirm both hawklets branched above the nest bowl, fairly close, but definitely with limited coordination and balance at this point in relatively high winds. Later in the day I was again able to observe hawklets branched on the nest tree.

https://www.youtube.com/watch?v=uBCbwQfDckY

https://www.youtube.com/watch?v=R4poQOZJydQ

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