BWHA - Juvenile fly...

BWHA - Juvenile flying with adults  

 Wendy Hill

The definition of FY is "Recently fledged young (nidicolous species) or downy young (nidifugous species) incapable of sustained flight". How do you code a juvenile BWHA flying with adults as it is clearly capable of sustained flight over a great distance? Thanks.


Topic starter Posted : 05/06/2021 11:56 am

Hi Wendy,


It's much too early for a young to have fledged and be out flying right now in Ontario - normal first egg date in central Ontario is likely around early May, and incubation is 28-31 days, so we should just be starting to see eggs hatching right now, certainly not fledged (which should take another 5-6 weeks). So, if you have a juvenile bird, then it would be a young from last year and not treated as a "young" in terms of the breeding codes. (individuals do not acquire "adult" plumage aspect until their second fall, i.e. when they are a bit over a year old).

So, I think you're most likely going to use the H code in this scenario, unless you observe any other "higher" breeding evidence such as evidence that the two adults are a pair.



Posted : 05/06/2021 2:23 pm
 Wendy Hill

@mike-burrell (shoot, I replied to this once but it seems to have disappeared into the internetz twilight zone)

Thanks! My mistake, I should have known this from my understanding of Red-tailed Hawk age plumage. The behaviour & moult limits of what appeared to be a juvenile bird flying with 2 adults threw me off. (I have seen this on 2 different occasions in the past week). I thought that it was too early to see fledged birds. So can I assume that the 2020 HY birds could stay with their parents until now and that their behaviour (soaring together and diving) was to sever the ties with Mom & Dad who are now tending to a new nest of chicks?

As a follow-up question then, what is the BE code once this year's chicks have fledgled? I have scribbled notes from one Atlas talk or the other, indicating that most immature raptors observed flying without a nest in sight, should be coded X. Understandable as there is no knowing if the actual nest was in that particular square or not. 


Topic starter Posted : 11/06/2021 10:46 pm

Hi Wendy,

To your first question, I'm not sure if one year-olds stick with their parents but I doubt it. I'd guess that your observation is just as likely a "random" one year old hanging near a pair. But I would have to do some research. Perhaps someone else knows.

To your second question, for fully fledged young of any species, if they're capable of sustained flight such that you can't be sure how locally they were hatched then yes, I think x would be appropriate. At that point it's likely past the species "safe dates" so something like H would not be suitable.

Posted : 13/06/2021 8:03 pm

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