Coopers Hawk (accipiter cooperri)

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JudyB
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Re: Coopers Hawk (accipiter cooperri)

Post by JudyB » Mon Jan 02, 2023 6:36 pm

Thanks for the update, ostrich - and please keep us posted. It does seem that the eagles with trackers are on a bit of a different timetable this year - and the weather has certainly been a bit odd. It will be interesting to see what the hawks will do.

Happy New Year!

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Maddy
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Re: Coopers Hawk (accipiter cooperri)

Post by Maddy » Thu Jan 05, 2023 3:55 pm

Thanks for the update! :thumlft:
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E9 is 7 yo now

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Fri Mar 17, 2023 7:26 pm

The pair at Colonel Samuel Smith park are currently building in a deciduous tree in the little bowl in the NE area of the park - this tree was used in a previous year, at least 2 years previous. Even the female was bringing a few sticks to the nest structure that's been started, so she seems to favor it.

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The very large size difference between the female and the male with this pair is very typical.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Apr 16, 2023 12:15 pm

Unfortunately as of Apr 16, it appears that the Colonel Samuel Smith park pair may have started focusing on another nest under construction approx 50m away from the small bowl, there has not been a clear indication of any further work on the bowl nest nor an strong indication that it is likely to be used. Another nest has been constructed in a very tall conifer along the north creek, which unfortunately will very likely be very hard to see from the ground - this is an area and a tree which has also been used in the past.

The pair at High Park have also been undergoing nest construction, as of Apr 10, also not in the same stand of trees and nest location they have used last year and in the past. This is also possibly unfortunate as the prior nest tree was also an excellent one for visibility from the ground. The current nest is also in the same general area, but approx 30-40m away in a tall tamarack tree - because of the surrounding woods it is also unclear if it will be very visible once foliage comes into the surrounding trees. However there are a couple of spots along the adjacent paths and slopes that might allow for some visibility.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Apr 16, 2023 12:23 pm

There is also a pair again in Dr. Martin L. Dobkin park after the initial nesting attempt and subsequent abandonment last year. The nest location that has been under construction as of Apr 16 is in the exact same tree where a few sticks were laid by the juvenile female that came into the area late last season. However this cannot be the same bird, as the current female this spring is another juvenile (SY) bird:

Female on Mar 30:

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The current male is in full adult plumage, as is almost always the case. But it is difficult to impossible to tell if this would be the same male or not.

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Over the past couple of days (Apr 13-15) the female has been regularly in the area of the nest late in the morning, although there has not yet been any indication of egg laying or any start of incubation. If this nest is used it should have some reasonable visibility from the ground.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Wed Apr 26, 2023 8:40 pm

The last couple of previous days I consistently found the juvenile female from the Dr. Martin L. Dobkin nest up in the nest and staying there - although she was sitting in a partly upright posture, and not fully flat as if fully incubating. So it has not been clear if she has actually laid yet and could be partly delaying incubation, or had not yet laid but might be getting close to doing so, in which case she would likely stay very close to the nest.

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This morning however, Apr 26, the female was up in the nest and laying pretty flat so that she was hard to see from the ground with this fairly sizable nest. So it looks very likely she has laid at least one egg by now. The male came in and flew right up to the edge of the nest, but she did not react or move, and he immediately left and departed the area. He did not seem to make any kik announcement call before doing so, which is a bit of an unusual behavior.

As of Apr 23, the pair at Colonel Samuel Smith also appear to be incubating, fortunately back in the earlier nest structure they built in the little bowl, despite having switch for a fair amount of time to building in the tall conifers closer to the north creek. This is good news as this nest is much easier to see from the ground.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Apr 30, 2023 4:18 pm

Apr 29: Checking the Martin L. Dobkin nest area, I found the female off nest in a tree across the path from the nest, this was a bit surprising given the weather which was steady light drizzle at the time. Over a period of a few minutes, the female remained off nest and was making periodic loud kek calls. I did hear one faint call that might have been the male in the same area, but I could not sight him to be sure. Because of the rain I would have assumed the female would stay on any eggs, so there is perhaps some uncertainty as to whether they have indeed been laid or not. However, today (Apr 30) checking again the female was on nest and in full incubation position.

Apr 29, the adult female on the Colonel Samuel Smith nest was also incubating so there is a more certain date range there.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Fri May 05, 2023 8:40 am

As of May 2, the pair at High Park, in tamarack tree just E of the Nature Centre is definitely incubating, with female visible on top of the nest in incubation position.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Wed Jul 05, 2023 7:14 pm

Unfortunately the nest at Colonel Samuel Smith appears to have failed this year - there may have been a hatch based on the behavior, but no young were visible and a few days after the nest appeared to be abandoned.

However the pair at Dr. Martin L. Dobkin has successfully hatched four young

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The adult male after having arrived nearby with a food item:

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From 06/17: https://www.youtube.com/watch?v=RHOllv_-EWw

From 06/21: https://www.youtube.com/watch?v=bSWo0lbD8ps

06/24: https://www.youtube.com/watch?v=jNhg1oUH9rg&t=6s

06/29: https://www.youtube.com/watch?v=zdiIgfenhr8

07/01: https://www.youtube.com/watch?v=KTt5naKp_Gg

All the hawklets have been branching the last few days, and I am sure that three for sure have fledged and have been moving back and forth to the nest tree from nearby spots. One might still be branching, but it has likely fledged as well.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Mar 17, 2024 9:44 am

I have been able to publish this article in the Journal of Raptor Research, as a result of observations from the Martin L. Dobkin territory in the spring of 2022. This was a quite unusual occurrence being a conflict post-incubation, and that of a juvenile female successfully challenging a full adult for a territory.

https://meridian.allenpress.com/rapt/ar ... m=fulltext

I here describe an occurrence of an apparent intrusion by a second-year (SY) female Cooper’s Hawk (Accipiter cooperii) into an occupied territory after incubation by a resident adult (after-second-year; ASY) female had commenced. The adult female was displaced from the nest on multiple occasions, resulting in an abandonment of the nest by the resident adults. The intruding female did not use the abandoned nest but briefly exhibited behaviors consistent with initiating a new nesting attempt. However this effort was also abandoned and no young were produced at the territory.

Perhaps more conflicts of this kind might be observed in the future?
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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Mar 17, 2024 9:54 am

As of Mar 6, the resident pair in Colonel Samuel Smith park are back on territory:

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Two adult birds were present in the little bowl in the NE area of the park, where there has been a nest in a number of the prior years. The adult female seemed to be most interested over a period of about 10min in breaking off sticks herself, although she did was not really flying them to any particular obvious structure under construction yet. The adult male was also present, although he was just roosting for most of the period, even in response to occasional kek vocalizations from the female.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Mar 17, 2024 10:01 am

The territory at Martin L. Dobkin park has also had some presence so far in March - as of Mar 10 and Mar 11 there have been birds present in the park. On Mar 10, in the west side woods, there were two birds, however one was a full adult, which I suspect was an adult female. And this bird in juvenile plumage was also present.

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There were a number of flights in which it appeared the adult female was flushing the juvenile along with some chasing flights. So this could certainly be a pre-incubation conflict for territory between adult and juvenile females, of the kind that is much more typically observed (as per Millsap et. al from 2019).

On Mar 11, there were an adult female and male present in the west side woods, with the female making occasional kek calls, after several minutes, the male flew out of the woods to the west, perhaps in order to do some hunting. There was not yet an obvious nest structure under construction.

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Re: Coopers Hawk (accipiter cooperri)

Post by ostrich » Sun Mar 24, 2024 6:04 pm

Mar 19, Mar 22 - both mornings the pair at Martin Dobkin have been present, in the west side woods, closer to the west edge of the park. On both occasions the female was roosting with the male present only briefly before flying out of the woods to the west. So far the male has been more elusive to get any shots of compared to the female.

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There does appear to be a likely partly constructed nest structure in a tree along the path a bit closer to the park edge than last year's tree. There is also another possible structure just S of the path, but it is more difficult to see. There is no sign of any construction at all in the tree that was used for last year's nest.

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