Coopers Hawk (accipiter cooperri)

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sat Dec 01, 2018 2:15 pm

This video has got some interesting footage of a juvenile Coopers hawk bathing.

https://youtu.be/5yNHg8GCwgc

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu Dec 13, 2018 4:56 pm

Dec 12 - I again had a brief sighting of an adult Coopers today, flying overhead a couple of streets north of the park.

Dec 16 - on my way back from xmas bird count, I had a brief sighting of an adult around 5pm a couple of blocks S of the park flying across the road between some industrial buildings, maybe looking for pigeons.

Dec 25 - around 11am I spotted a Coopers roosting on a light standard beside the road about 50m N of the church (a main block N of the park). It was interesting that a northern (abieticola) RT that has been around for a few weeks now was also roosting on top of the church at the same time.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Fri Dec 21, 2018 7:42 pm


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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Mon Jan 07, 2019 6:21 pm

This is an article on a possible Coopers hawk-northern goshawk hybrid.

https://adventuresinmothland.wordpress. ... Ouxx8wel6w

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Mon Feb 04, 2019 10:14 am

Feb 4 - today at noon I had my first sighting in a while, of an adult Coopers up on top of the church, present for perhaps 10-15min.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Mar 12, 2019 6:03 pm

Mar 11 - this morning I went out to the park at about 6:15 for the first time to look for activity, at about 6:45 I did have a Coopers glide into the park from the west entrance, and glide around eastward for a bit, before turning and heading towards the daycare yard and trees towards the S edge of the park. I couldn't tell if it stopped at all, when I walked over to look I couldn't see anyone in the trees. So I'm not positive if this was one of the residents or not.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Mar 17, 2019 8:48 pm

Mar 15 - I went out to the park at ~7am to check on activity, and there was already one Coopers sitting on a tree branch in the area at the S edge of the park, and both adults were present (although I could only hear the other's vocalizations from some where off to the right closer to the building). The visible bird had some type of food, so it's possible there was a delivery. After several minutes there were more vocalizations from the other bird, and the visible one flew off to the right to the park edge and out of sight.

https://www.youtube.com/watch?v=tm2sgITHI-M

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Tue Mar 19, 2019 7:13 pm

Mar 19 - today there was noticeable activity in the park, passing by the park at about 9:30am, I noticed both adults perched together in the area close to the existing nest:

Image

The female appeared to be just roosting while the male was going back and forth a couple of times and trying to break off sticks, so this was the first definite nest building activity I have caught thus far

Image

Image

Going by the park again around noon time, the female was still sitting in the same area, so this is also a sign of increasing presence in the park over just short pre-dawn activity.

At ~6:30pm another check had the female once again roosting around the same area, with the male flying past from the park edge, heading in her direction. He did not appear to stick around, but there were quite a bit of vocalizations.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu Mar 21, 2019 5:10 pm

Mar 21 - Both yesterday and today, checking the park when passing by both early in the day (~9:30 am) and late afternoon (around 5:30pm) there was adult presence (female) in the trees in the vicinity of the nest. This is indicating that the female is spending substantial amounts of time in the park area now.

Mar 22 - This morning at ~10am, when walking along the sidewalk just off the W entrance of the park, an adult flew low over the road and into the park going past the nest tree and further on, but upon checking there was no sign of either adult in the trees, so it did not stop to roost on this occasion. This evening the park was empty.

A recent article on urban accipiters.

https://www.allaboutbirds.org/seeing-mo ... agination/

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Mon Mar 25, 2019 6:35 pm

Mar 24 - I visited the High Park Coopers territory early in the morning to look for courtship activity, and found the adults vocalizing close to last year's nest tree. There was a brief copulation, followed by the female leaving, although periodically she was continuing to vocalize from different locations close by the same stand of trees. I did see the male break off a couple of sticks and fly them up into last year's nest.

I saw my local female briefly a little later in the morning, and around noon time after going out, I found an adult up on top of the church north of the park.

Image

Image

Mar 25 - my local female was again roosting in the park around the nest area at around 9am.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu Mar 28, 2019 7:55 pm

Mar 27 - I was able to check the park fairly early at around 7:15am, and both adults were roosting near the nest, the male did make two or three trips back and forth to break off small sticks and fly them up to the nest during the time I was watching.

Mar 28 - Around 9am one adult was roosting near the nest, interestingly I spotted another accipiter a few minutes later farther up a block further north from the church, but I don't know whether one of the residents would normally wander up that far.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Apr 07, 2019 5:26 pm

Apr 4 - I went out to the park at about 9:15am, I did not see the female in the typical spots near the nest tree, but then I heard some whaaa vocalizations coming from further back, along the N edge of the park. I found the female roosting fairly low in a branch of the small trees/bushes along the N edge right beside the N walking path exit to the park.

Image

In high resolution it appeared that the female may have eaten recently, as there was some blood on the feet and a bit around the edge of the beak. She continued periodically make whaaa calls which are her typical vocalization when communicating with the male, although he was not anywhere in sight. However she may either have been making calls to request food delivery, or she may have been able to see him somewhere in the distance. However the male did not make an appearance during the period I was there. However the shots of the female also did yield a useful piece of information, the middle toe on the left foot above has somewhat of an unusual/bulbous shape, as if perhaps an old healed fracture or some other injury to the toe. Upon going back and reviewing other shots of the female from last year, this shot from almost exactly a year ago shows the same kind of unusual shape to the middle left toe. This is pretty good confirmation that it is the same resident female in the territory.

June 22 2018:
Image

Footage of the female vocalizing:

https://www.youtube.com/watch?v=TlYyId7bVzw

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Apr 07, 2019 5:31 pm

Apr 6: Going out in the morning around 8am, both adults were in different branches of the nest tree below the nest. I hoped to get close shots of the male especially for identification purposes, but before I could return with my camera the male flew up briefly to the nest, and then flew to one of the usual roosts just away from the nest tree. The female took some interest in a squirrel which was moving around high in the nest tree but did not make any other moves toward it.

Later in the afternoon around 1:15, I found both adults roosting together near the common perch, and after some quick vocalizations from the female the male moved and I was able to observe copulation. As was the case last year the male is markedly smaller than the female, which is often the case with Coopers:

Image

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu Apr 18, 2019 7:22 pm

Apr 16 - I have not been able to check the nest for the prior week, but on checking the nest area in the morning, both male and female were roosting together close to the nest area. The nest structure appears to have been added to visibly.

Apr 17 - in mid morning, I caught the female briefly on the nest poking around in the rim before flying back off to the trees.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu Apr 25, 2019 4:49 pm

Apr 21 - I saw the adult female sitting on the nest for the first time in the morning in incubation position, which is likely at least a sign of impending egg laying, but might or might not be a definite indicator of actual laying.

Apr 23 - I did not see the female on the nest either of the times I checked, on one occasion she was roosting in one of the usual spots nearby the nest tree.

Apr 24 - In the morning, I saw the female just flying from off the nest from the west direction up into the nest. She appeared to be rummaging around in the bowl during the time I observed. Later in the day she did again appear to be in an incubation position.

Apr 25 - in the morning about 8:30am the adult female was on the nest, standing upright at the edge of the bowl, but did not seem to be overtly sitting. Shortly thereafter she flew off the nest low over the houses immediately N of the tree, and she was vocalizing, it could have been some delivery or arrival by the male. This evening around 5pm she was again in the nest in the same upright position, but not in overt incubation position.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Mon Apr 29, 2019 4:21 pm

Apr 29 - I am now tentatively pretty confident that incubation has started, yesterday and today I have been consistently seeing the female on the nest after several checks during the day. Yesterday both male and female were present in the morning (around 7:00am), and later in the morning at about 11:30am. The female was on nest in the early evening at around 6pm.

Today the female was on nest at ~9:30am, and was also on nest when I went by at ~5pm and 6:30pm, but the male was not around. It was raining and temperatures have been relatively cold today so it would make sense for her to be on nest if there are eggs.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Thu May 09, 2019 6:59 pm

May 9 - I have been regularly seeing the female on the nest in incubation as normal for the past couple of weeks, and occasionally seeing the male as well. Today around 3pm I went by the park and sighted an adult on the nest flat in incubation position, then walked to the other E end of the park and spotted what appeared to be the male in the big oak tree in the NE corner, pulling at a fairly large prey item (it looked completely deplumed but appeared to be roughly robin-sized).

https://www.youtube.com/watch?v=EN87CEJjmvI

I watched the adult working on this prey and consuming parts for approx 10 min before I left for an errand. Returning briefly about 15min later the adult was from the tree, but both adults were close to the nest (one roosting across from the nest tree, the other in the nest. So probably after finishing processing the prey item it was brought over for the female but I didn't see the delivery.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Wed May 15, 2019 5:32 pm

May 10 - In some of the wet and somewhat cold weather that's been around quite a bit this spring, I found the male roosting near the nest and looking pretty bedraggled in the rain:

Image

May 13 - in addition to seeing the female in the nest consistently, I sighted the male in early evening again roosting across from the nest tree presumably after a recent visit or food delivery.

May 15 - Early evening, the female was in nest and the male roosting in his usual spot across from the nest tree.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Wed May 15, 2019 5:59 pm

There was also been a very interesting nesting situation at another territory in Colonel Samuel Smith Park, down on the lakeshore, right now there is a pair nesting in a deciduous tree in the NE corner of the park. The unusual aspect is that both nesting birds are SY birds (still in juvenile plumage).

Female:
Image

Male:
Image

This is a highly unusual situation, breeding SY females are not common, but are known in Coopers hawks, but SY males are rare. There is some data on this in Robert Rosenfield's book

https://www.hancockhouse.com/collection ... 5218945069

In the Wisconsin long term study described, only 2% overall of nesting attempts involved a SY male, it is also interesting that the occurrence of SY males also seemed to be strongly biased towards a relatively new colonizing population that is growing. On the surface this seems unlikely to be the case for CSSP since Coopers hawks have been a common nesting bird in the city for a substantial period of time.

There have also been reports that are unconfirmed that there might be a second pair of breeding adult birds in the park, as well as possibly a third pair. If either of these are present it would also make the density of nesting territories very high for this park.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sat May 25, 2019 9:03 pm

It appears perhaps unfortunately that the nesting attempt at CSSP park has ceased, at least for the time being. However there is still presence by the pair and some interesting behavior.

- 05/17 a visit to the nest area didn't seem to have the female visible on the nest, although on many nests it can occasionally be hard to see an incubating female if she is flat on the nest and her angle doesn't allow her tail to be easily visible sticking out over the side.

- 05/19 At 09:15, the nest again did not appear occupied, but after a short time near the nest area some kik calls were audible by the SY male. He was spotted in a tree fairly close to the nest.

Image

Over the next 10-15min, the male did show behaviors of flying occasionally to different tree branches and pulling at them, attempting to break off, consistent with typical nest building behaviors.

Image

Image

One flight was observed possibly carrying a stick to a conifer on the opposite side of the big bowl/depression directly west of the nest tree (approx 30m away), where glimpses of what presumably was the female were visible without a clear view. However some vocalizations which were likely copulation were heard from the tree shortly afterwards.

05/20: At ~06:35, the nest again did not show any sign of occupation, but within 5-10min some kik calls from the SY male were audible from adjacent trees. Searching the trees did locate the SY female, with deplumed (appeared to be passerine) prey which she was consuming. Within seconds the SY male flew in from some nearby location and copulated with the female.

Image

The male left after copulation, and the female eventually flew into a conifer on the near side of the large bowl (closer to the nest tree, within 10m). However any new nest structure was not clearly discernable in these trees.

05/23: At 07:00, nest empty, and only caught one kik vocalization and a brief flight of one of the SY birds flying down the large bowl in a southward direction.

05/24: 06:15, from passerine alarm calls, the SY male was located in the vicinity of the nest site, again engaged in stick breaking behaviors (moving periodically to different tree branches and twisting with beak),

Image

After several attempts a very long branch was flown away in a southern direction to another small bowl filled with mainly deciduous, and a couple of coniferous trees, which is ~150-200m south and slightly east of the prior nest tree. Finding the SY male in these trees, there was a very small start of a nest construction in one deciduous tree, with the male bringing sticks to it.

Image

Image

So it appears that the initial nesting attempt (which certainly seemed to have the female in genuine full incubation for a noticeable period of time) was abandoned for unknown reason. Presumably abandonment occurred sometime around Apr 17, consistent with other reports from other park birders. Perhaps some reasons could be:

1) Human disturbance: under normal circumstances territories in the area have always seemed to be very tolerant of human activity, so just ordinary presence presumably would not cause this unless there was something especially different about this female's behavior. There have been some concerns expressed about potential drone activity nearby, as one drone operator was observed fairly close to the nest (although not flying directly near it), this was on 05/21, but it leaves open possibility there could have been other previous drone flying. Whether this would affect them to the point of abandonment is unknown.

2) Egg predation by nearby mammalian predators, there are quite a lot of squirrels in the trees immediately surrounding the nest tree, although a squirrel seems less likely to be able to predate eggs from a Coopers female (other than perhaps factoring in that the bird would be nature of being SY be relatively inexperienced). More likely a scenario would be raccoon, as these are definitely present in CSSP and are seen in the area near to the nest.

3) An inability of the SY male to provide food deliveries serious enough to cause nest abandonment. There doesn't seem to be any significant indication of this though, and the fact that food deliveries certainly seem to be continuing from the male post-abandonment certainly suggest his hunting is at least adequate. The biggest hunting burden that might be difficult for the SY male would presumably occur after hatching as opposed to before.

It also seems clear that the nesting abandonment has not resulted in departure from the territory, and the pair have gone back to a number of courtship behaviors, it remains to be seen if there is a full nest construction or not. I don't know if they would actually progress again all the way to egg laying (other pairs in the general geographical area would be getting close to hatching in the next week or so, so they would be several weeks late). If they did so, would they be able to successfully rear young hatched a full month later than the normal window, also being SY birds, is also unclear.

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