Juv Male or Female Sparrowhawk???

FUDGEY · #1 (**permalink**) 14-03-2011, 06:37 AM

This has been annoying me for a few weeks now. My friend thinks its a Female, but I think its a juv Male. I am not sure if it is, but he is convinced. Any way I will leave it to some of yous on here who are far more clued up on me. Two photos of a mature Male and the undecided one on the same stump so you can compare sizes. Hope you can clear this one hope, thanks.

FUDGEY · #2 (**permalink**) 14-03-2011, 06:39 AM

I think the second one looks slightly bigger, but I think this is because its puffed up a bit. I would have thought that if they were different sexes you would see a considerable difference in size. Any way like I said I will leave it to the experts.

FUDGEY · #3 (**permalink**) 14-03-2011, 07:09 AM

Just found better pic for comparison....

RobinP · #4 (**permalink**) 14-03-2011, 09:06 AM

I'll go for female, not sure if it is a juv or not though.

Robin

STYRBJORN · #5 (**permalink**) 14-03-2011, 10:36 AM

The one in the upper pic looks to be a juvenile male; the slate grey back is a give-away. The lower pic is an adult female, with the brown back. Remember sparhawks show reverse sexual dimorphism, which is fancy language for the females are bigger than the males.

Google "sparrowhawk" & look at the RSPB site.

FUDGEY · #6 (**permalink**) 14-03-2011, 12:34 PM

Ty Robin, Im still unconvinced

Ty to STYRBJORN, but I probably havent worded it correctly. I know the top one is a Male (mature) its the second photo I am not sure about. Surely if it was a female it would be more obvious of a size difference????

STYRBJORN · #7 (**permalink**) 14-03-2011, 01:29 PM

Quote:

Originally Posted by FUDGEY

Ty Robin, Im still unconvinced

Ty to STYRBJORN, but I probably havent worded it correctly. I know the top one is a Male (mature) its the second photo I am not sure about. Surely if it was a female it would be more obvious of a size difference????

My misreading. I still say female, on the basis of the colouration. A yearling? They are long-lived, and so slow growing. I'm open to correction though. Grabbing hold and having a close look is probably not a good idea!

Ferret · #8 (**permalink**) 14-03-2011, 02:28 PM

I don’t think I can determine the sex of this bird but I think I would guess at female hatched last year, main moult starts in May and will really start to show in June (according to Dick Forsman in The Raptors of Europe and the Middle East) so it would still be showing juvenile plumage. Size is not always a good guide Collins Bird Guide puts Males at 29-34cm and females at 35-41cm body length so only 1cm between a large Male and a small Female.

Ferret

Dogghound · #9 (**permalink**) 14-03-2011, 07:51 PM

You need to look at wing length with immature birds to age them, you cant sex them on apparent size unless it is significantly clear. The bottom bird is definitely a first winter. Do you have any shots of the rump/nape? it is early although this is usually where adult feathers appear first.

From this angle your male is at least 3 winters old.