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 Forum Index > Raptors Other than Eagles > Other Raptors -- Questions, Information and General Discussion
 Coopers Hawk (accipiter cooperri)
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By: ostrich (offline) on Monday, March 20 2017 @ 11:03 PM EDT  
ostrich

Some recent local observations:

Mar 16 - In the park before sunup, I again had both local adults present and making typical kik announcement vocalizations from the male, and some either single note cacks or kek sequences from the female. They started out in the NE corner of the park, and spent some time in the large deciduous tree just outside the N border along the E edge. They also at one point moved over to the conifers which also line that same N edge of the park border. However there was no sign of any obtaining of sticks or actual nest building.

Mar 17 - approx 6pm I came across an adult roosting in a tree in a yard along the eastern park edge about 40 yards N of the park boundary. Perhaps it was hunting the yards but seemed to be pretty static and generally roosting.

Mar 20 - I got the first activity starting at 6:58 with the start of announcement calls from the male. This morning I followed about 40min of activity in and around the park, but interestingly there was still no sign of actual nest building that I was able to see. The male started out within the park in NE corner in the usual tree, but female responses seemed to be coming for several minutes either more distantly from the NW corner, and then subsequently to the deciduous tree just outside the N edge.

- after several minutes the female flushed and flew down S and either briefly paused or flew out across the road from the SE corner. The male followed to a roost in a tree in the far SE corner, but after a couple of minutes also flew out of the S edge of the park. I assumed this was going to be the end of the morning activity, but I walked around the S border to the street to see if I could spot where they went, and then around back into the park near the W end. This took a few minutes and suddenly as I got back into the park I saw one of the adults come back into the park from the SE and land in the trees in the NW corner. Over the next 5-10 minutes I then saw movement to a few different locations, including a tree along the farthest W edge, a conifer just N of the NW park corner, and the conifers along the N park edge.

When I went back out approximately 20 min later I was surprised to spot one of the adults in a tree directly north of the park several yards down, which is where I'd seen the juvenile female earlier in January. After some kek vocalizations she then flushed and flew to the SW which is the last I saw.

I'm not sure what all this pattern means, it's definitely later than it's been in some other years for actual nest construction to start, although there's still a fair mount of time before any egg laying would normally happen. But I wonder if the female hasn't yet found a candidate tree she is happy with as a possible nest location, and they're continuing to check different locations.



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By: ostrich (offline) on Monday, March 27 2017 @ 11:42 PM EDT  
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Mar 23 - I went out about 7:05 and didn't see anyone around in the park, so after walking the perimeter I decide to drive around the surrounding area a bit and see if the adults were moving around anywhere else, I went first to some streets to the S of the park, but didn't see anything down there, and checked some areas just E of the park. When I finally ended up subsequently on a street about 400m NE of the corner of the park, I happened to spot a Coopers in a relatively sizable deciduous tree that might be sturdy enough for nest structure so I took a look. It turned out interestingly that this bird was a male I think, and juvenile, so not one of the residents. By the time I came back around to the park both adults were in there and roosting near the N edge in different trees. But again in the time I had, they just both sat roosting, and occasional exchange of kek vocalizations, there was no nest work or sticks at all. The male flew off through the backyards at one point perhaps hunting, but the last I saw he was back and still roosting nearby the female.

Mar 27 - This morning was quite interesting, right on cue at about 6:50 I heard kik vocalizations from the male in the NE corner of the park, followed a couple of minutes later by the arrival of the female into the same tree with some exchanges of kak and kek vocalizations. About 7:05 there was a copulation, and around 7:10 one of the adults flew straight out N in the direction of the street that goes directly N from the park edge. After walking to my car and starting to drive along to hopefully pick them up again, I very surprisingly spotted the male sitting in a very small nest structure in a similarly small tree right at the corner of the street (probably no more that about 15-20 ft off the ground. The structure itself seemed wedge into a reasonably sturdy crotch, but that would be far far closer to the ground than I've ever seen a Coopers nest. And the structure itself was no larger than the male itself, so it would be very hard to imagine how 3 or more young could be raised inside it.

Subsequent to this, I picked up vocalizations from the female further up the road, and in response the male flew up in that same direction, directly towards the largest conifer in a yard towards the end of that street. I suspect but am not positive that he brought a stick up there, as I heard what sounded like a snap of a branch when he flew, but didn't see if he was carrying one. But it may mean they are also looking at a nest structure in that conifer, while the male was doing this, the female was perched on a high antenna in a yard yet a little further north. By the time I went around to take a closer look at that conifer and came back around, the female had left that perch. I spent around 10 min just looking around at some other somewhat larger trees around the immediate area without seeing anything interesting, and by about 7:40 made another pass back through the park. The adults were back there, until the male flew out low to the E a few minutes later (which might have been him going off to hunt). The female interestingly spent a few minutes hopping around in one of the deciduous trees and looking like she was going to try to break off sticks, either testing ones by hopping onto them, or gently grabbing ones and twisting a bit which they sometimes do with their beaks. But then she quit without actually doing so.

But this at least seems to be some sign of more nest building type of behaviors starting - although it's unclear what it might mean in terms of possible nest locations - the one in the low tree I'd be surprised if it made the cut as an actual nest.



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By: ostrich (offline) on Monday, April 24 2017 @ 11:59 PM EDT  
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I am catching up on recent activity - for the past several weeks the Coopers have been continuing presence for a short period in and outside the park, but then settling back into areas inside the park. Although for a while it seemed like they might not do any nest building in the park at all, by Apr 1 the male was beginning construction of a new nest in a tree near the W entrance to the park. They've never built in this tree before, although the original 2012-2014 nest wasn't too far from here



Nest after about a week of construction (Apr 8).



For quite a while the male, and occasionally the female, were continuing to break off sticks from the adjacent trees and bring them in. Even after construction had been going on for quite a while, the nest structure itself was pretty small, although by about the 17th it was finally starting to look somewhat more substantial. Even now it still looks on the small side for a Coopers nest, but seems to be large enough I guess to be adequate.





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By: ostrich (offline) on Tuesday, April 25 2017 @ 12:15 AM EDT  
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In addition to nest building activity, there has also been typical food deliveries by the male and courtship activity,

Apr 8:





Food delivery (Apr 11):



Some footage of the adults where I found the male already with a food delivery on a stump fairly close to the new nest tree (Apr 14)

https://www.youtube.com/watch?v=N9QBlWrIWyc

Between Apr 14 and Apr 19 I was continuing to see the female more and more consistently in the trees near the new nest, which is typically a strong sign of intended use and upcoming egg laying, however Apr 20 after both adults were present early in the morning, did not seem to be there the rest of the day and early evening. This made me think there might be a similar sudden abandonment of the park as there was for unknown reasons last spring. However Apr 21 she was back, and she was for the first time seemingly in an incubation position on the nest. So I am

The past 3 days the female has been maintaining presence on the nest consistently with their being eggs. She has been in incubation position a good portion of time However I have also seen fairly lengthy periods when she is either standing in the nest or on the rim, or is on a nearby branch. I have also witnessed some periods when the male has delivered food that it has taken her a fair amount of time to end up back on the nest. I believe this is pretty consistent with indications of delayed incubation, so probably whatever clutch is still in the process of being laid. Saturday and Sunday were fairly warm during the day and may not have needed as much incubation time under these circumstances.



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By: ostrich (offline) on Friday, April 28 2017 @ 08:28 PM EDT  
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I am pleased to say that based on my observations over the past several days, I'm pretty sure now that a full clutch has been laid, and delayed incubation has ended, with full incubation starting yesterday.

From Apr 23-36 I continued to see the female consistently, on occasion in a flat incubation position, but pretty consistently standing either on the nest rim, or on a nearby branch, or occasionally in nearby trees, particularly on occasions where the male was also around. This was the case even on Apr 24, when the weather was light rain for a good part of the day and relatively cool.

Apr 26 - I observed the female again standing up on the rim of the nest in the morning, and again when I came home in late afternoon. When I went out again around 7pm, I observed the female standing inside the nest, not on the rim, but quite low, yet not in a flat incubation position. She held that position for quite a while, and her tail was moving side to side quite quickly while I was watching. It's very difficult to tell, but I suspect that might have been an actual laying of an egg.

Starting the morning of Apr 27, every time I've gone out, I've found the female flat on the nest in a full incubation position. So I am currently recording Apr 27 as the start of full incubation. Based on an approximate 2 day interval between eggs, if Apr 26 was indeed the last egg laid, my best guess would be 3 eggs, the third egg is normally when full incubation would start. It would also be consistent with the history of this territory, which most years has produced 3 young, but never more than this.



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By: ostrich (offline) on Friday, May 05 2017 @ 08:16 PM EDT  
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An interesting article on eye coloration in accipiters.

https://avianrecon.wordpress.com/2014/1 ... ye-colors/



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By: ostrich (offline) on Wednesday, June 07 2017 @ 09:49 PM EDT  
ostrich

I'm happy to say that today (June 7) I got a confirmed observation of my local female with some food on the nest and making movements to pull at whatever was in her feet and offer it into the bowl. So that's a pretty good indication of a completed hatch.

I've been checking the nest as often as I can since Saturday, when the window for potential hatching should have been starting based on my previous observations of incubation. I've been suspecting since then that there might have either been a hatch or one in progress from the female's behavior (indications of restlessness, gradually from day to day seemingly sitting higher in the nest, etc). However there was no clear indication of a feeding which would confirm a hatch. On Saturday I definitiely saw the male arrive in the park with prey, and the female left the nest as a result, but there did not seem to be any of the food brought back to the nest.

On Sunday and Monday I also caught arrivals by the male to the park, but not actually seeing him fly in I couldn't be sure he had food (most of the time if he arrives he has food but occasionally he will pass by the area without). On none of those occasions did I see any food brought back to nest, but the female may have gotten some from him, sometimes I can find where he has landed, other times I can't. Yesterday was drizzly for much of the day so it was difficult to check.



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By: ostrich (offline) on Monday, June 19 2017 @ 08:45 PM EDT  
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It's taken a while but I've managed to finally catch some brief sightings of at least one hawklet in the nest, although most of the time they're still down below the rim of the bowl. On Friday I finally was able to see a head just peeking up over the top of the bowl, and on Saturday I caught a brief glimpse of a hawklet up high enough in a horizontal position to just be able to see the top of the head

The hawklets look to be still fully covered in down from what I've been able to see, and they're able to thermoregulate in normal weather conditions, we've had quite pleasant temperatures the last 4 days, with occasional brief rain showers. I've noticed several times over the past 3 days the female roosting off nest in an adjacent tree branch, watching the nest from there, so that's a good indication they don't need to be constantly brooded.

https://www.youtube.com/watch?v=U16w8LCjk1k

This evening I spotted the female giving the hawklets a late feeding, and this should confirm at least two hawklets, I could see one head clearly, and the female was pulling off pieces and offering them down into the bowl in a different area from where the visible hawklet was, so that should be a good indication of at least two.



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