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Thread subject: Male v Female
Name Date Message
Tiger 07/30/05 03:47 am Excerpt from Welsh osprey diary.

If Roy Dennis cannot tell wqhat chance have we?

Very interesting point about female mating. They choose the first male they meet! [probably the one with the biggest fish account :)) ]

Master and Miss Osprey?
Discovering the sex of the chicks was never going to be an easy task. At this stage in their development, male and female chicks appear very similar and only a few minor differences allow us to tell the sexes apart.

The measurements and weights that we recorded from the chicks at the ringing two weeks ago were sent to Roy Dennis in Scotland (who organised the colour-ring scheme that applies to ospreys in the UK and Spain) so that he could make an informed judgment.

The weight of the birds is taken into consideration - females are usually bigger and heavier than males. A female will also have a longer tarsus (lower leg) than a male and when they are ringed, the ring will be a tighter fit on the leg of a female chick.

Taking all of this into account, Roy suspects that the older chick is male and the younger chick is female. It is not guaranteed, however, and we will only know for certain when they have got their full, adult plumage (males have more white on their heads, with fewer of the dark speckles).

'If we do have a male chick, then there is every chance that we will be seeing him back in Wales in a few years time.'It could be a while before we know conclusively, as the chicks will still be in juvenile plumage when they head for Africa in September and will not be back in Europe for around two or three years, when they are ready to start families themselves.

If we do have a male chick, then there is every chance that we will be seeing him back in Wales in a few years time. Males have a very strong instinct to return to their natal site to breed and have been known to nest only a few hundred metres from where they hatched.

The female's nest location will be determined by whichever male happens to attract her during her first breeding season.

Celeste 07/30/05 06:28 am Your absolutely right....At this point I just refer to both of them as "she", whether they are male or female....
Lori In Tampa 07/30/05 08:24 am S/he is also a safe way to cover BOTH bases when refering to sex.
Marie 07/30/05 09:38 am Great information....never easy is it to get into Birding.Roy Dennis didn't even talk about the necklace in this bit that you typed up Tiger. It would be hard to believe that a bird with a very pronounced necklace would be anything other than a female.
Tiger 07/30/05 05:31 pm Yes but the chance of a chick coming back is quite low. No chick born in England or Wales in the last four years has yet returned.
Tiger 07/30/05 05:32 pm Doesn't our Betty have the whiter head?
karen 08/01/05 10:07 am Thanks very interesting info.

Copyright © 2006 DPOF

Tom Throwe
Last modified: Sat Feb 18, 2006