Hancock Here: A specific Challenge

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gemini
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Hancock Here: A specific Challenge

Post by gemini » Fri Jan 14, 2022 12:12 pm

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A specific challenge, question or dilemma faces me.

After 65 years of describing one behaviour one way, I believe I have had an 'aha' moment, all of a sudden seeing something in a different light.

A few observations are, I believe, now backed up by a proof from our cams. But I am seeking more images and observations from you, our eagle watchers.

I have two notes, both relating to seeing a chick from one nest fly into another nearby nest. At branching I had personally not witnessed, nor even until recently, suspected, that chicks of one nest might visit another nest. I had thought about this option but never having seen even a hint of this behaviour, I had dismissed it. Now this seems such an obvious happening. The fledged chick now seems to obviously identify a nest with food. This of course is different from my early wilderness fledgling observations. Never had I seen wilderness fledgling return to the nest for food. They largely did not feed until abandoned and then they migrated. And of course, why worry about returning to a nest when every tree, rock, or stump is a safe, secure place to rest. But our urban and suburban eaglets are different. Our local chicks are frequently seen returning to the nest after fledging. I have often said this was because they did not find safe and secure places to quietly sit and not be disturbed by dogs, baby carriages or screaming kids. And recently we have seen in the very busy urban areas that fledglings often return to the nest -- sometimes even being fed! Why would a fledgling just identify its nest with food? Why not consider any nearby nest a source of food? Indeed!

So, can our eagle enthusiasts find me the specific data to confirm this behaviour? How many screenshots or videos record this action? Do you have observations of this happening but no photographic support? I would love to collect up this data. How commonly do chicks move from nest-to-nest post fledging?

Over the past few years, I have had some of my best observers indicate that only one or two chicks were present -- and this conclusion was from monitors who almost daily observe specific nests. I, or someone else, would arrive late in the season, or the regular monitor may have had the late season surprise observation of a different number of chicks. We had always assumed that the reserve, lazy or perhaps less active chick simply did not show up on any of their earlier observations. Then at the last moment, perhaps during the last two weeks of the eaglet time in the nest, another chick is finally seen. Observing different numbers of chicks at different times the same hour, day or week is common. It is so easy for a chick to hunker down out of the wind and simply not be observed. This is more common than always seeing the same number on successive visits. But is there another explanation for this additional chick? Well today we know the answer can be a resounding yes. We have now seen it on our live streaming CAMS. So, my question is: How common is this movement of chicks from one nest to another? Can our eagle observers around the country get me the benefit of their collective observations?

Obviously, the new arrival is already fledged. Do fledged eaglets regularly visit other nests? Is there some preference for empty nests vs eaglet occupied nests? Certainly, the latter is more likely to contain food! Is there conflict between resident adults and a visiting eaglet? I am hoping to get as many comments on this issue as possible. I am particularly hopeful some of you have supporting visuals.

Some of my observations:

The White Rock CAMS in 2020 were the first to conclusively show a fledgling fly from its nest directly into the adjacent nest. These two sets of adjacent nestling chicks were a little over a month difference in age. What makes this observation so telling is that our WR CAM eaglet had fledged and both the parents and fledgling had departed on migration. Then one of the pair of eaglets from the adjacent nest #040.5 flew directly from its nest into the WR #040 CAM nest. These nests are about 280m apart and readily visible from each other -- and our WR CAMS. Wow -- this flight was recorded on the CAM records!

Also, in 2020 one of our most reliable monitors, one who visits the nest in question at least 4 or 5 times a week, gave me an update that nest #096 had again 2 large chicks, about 10 to 10.5 weeks old present. The very next day I happened to be passing this nest to evaluate building a new nest two territories down River Road for a pair who had their nest tree blown over. There, standing so tall and obvious in #096, were 3 huge chicks. I quickly took several photos and called monitor Kathy. I don't want to suggest she did not believe me, but she arrived within 12 minutes -- to see two chicks.

Now here is where this gets more complicated. She immediately spoke to two residents of the adjacent Floating Home community who looked directly up at the nest. Each reported seeing three large chicks in the past couple of days. Then Kathy turned around to again look at the nest and there were 3 huge chicks in plain sight on the nest. She took more photos. Did the third chick of this nest regularly not stand up at the same time as the others or did another chick arrive on the scene? Who knows -- there are no CAMs running 24/7 at this nest site? I did not yet let Kathy off the hook as I had not yet made the following observation.

The eye-opening nest in 2021, #490 on Arthur Drive, was also on a regular route of Kathy and myself. In fact, #490 had been a very much disturbed nest the previous year during a road work project and we got to know the pair well -- after the eggs had been abandoned due to heavy equipment work at the base of the nest tree. This nest had one young in a quite flat open nest that was easily viewable from about 125 m away. Then on this day -- there are two young. One is standing off to the side and the other is standing mid-nest picking at food. Most interesting was the presence of the adult female -- sitting 1.5 m away on a branch, staring at the nestling feeding. But what was most noticeable was the female’s behaviour. The whole time she was intensively viewing the eaglet that was eating. And she was totally viewing the eaglet with her head completely turned upside down -- in that incredibly inquisitive behaviour frequently displayed by eagles in new challenging situations. My obvious conclusion was that she was very surprised at viewing this possibly "new" chick in her nest. This was my conclusion at the time, and this led to me putting Kathy's #096 observations into a more sympathetic light. I immediately called Kathy to tell her my hypothesis. She immediately said this nest only had one chick -- a nest she observed almost daily. We both accepted the second chick was a new arrival.

Have I now got this right? Is this movement of flying fledgling from one nest to another a more common or even infrequent happening? This is what I hope you will help answer.

On several occasions throughout my life, I have been suddenly so surprised to have so regularly seen 1 young (or 2 young) then, after many weeks, all of a sudden seen an extra-large chick. In these latter cases, particularly where the extra chick is still in the under 9 or 10 weeks of age (after which the brown head feathers lie flat), I have readily justified the extra chick as simply an additional chick now with its head up. But with older chicks is that always so? I hope some of you have observations on this issue.

Thanks and keep safe,
(This note can be reposted anywhere to help get some responses! Thanks!)

David Hancock
Hancock Wildlife Foundation
604 761-1025
davidhwf@gmail.com

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19313 Zero Avenue,
Surrey BC Canada
V3Z 9R9
"Home of Live Streaming Web Cams"
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