Tagged cuckoo question

[Wild-Woman]

This is probably a dim question but one I need to ask. The BTO's satellite tagged cuckoo project is providing some very surprising and interesting information about these incredible birds on their journey to Africa but I wondered why they seem to be using just male birds? Or did I miss something?

I'm amazed to hear that one flew over the Alps!

[FUDGEY]

Probably because Males in life are usually more reliable Im off see yous

[Wild-Woman]

Originally Posted by FUDGEY

Probably because Males in life are usually more reliable Im off see yous

Hmm. Interesting answer Fudgey.

[Ladywell]

He's obviously off to another planet, Wildwoman!!

[dunlin]

They used a stuffed female cuckoo and played a recording of the female cuckoos call to trap the birds in nets
The birds they wanted to use had to be a certain size/weight so unless the males are bigger than the females im not sure either

[RoyW]

The technology for the satellite tags that allowed this project to go ahead in the first place, has barely reached the limit where the tags are considered small enough to use on birds the size of Cuckoos. When they were out trapping Cuckoos many of those that were caught had to be released without having satellite tags attached because they were considered too small, only the largest individuals had the satellite tags attached.

Without looking up size/weight measurements for male and female cuckoos, I can't say for certain that this is correct, but I wouldn't be surprised to find that males tend to average larger than females, and only the larger males are considered to be large enough for the tags.
An alternative possibility is that the trapping technique used when they were catching the Cuckoos to apply the tags was more effective for males (eg. perhaps tape lure was used, and this attracted males trying to see off a potential intruder?).


Edit: Assuming that Dunlin is correct that female calls and a stuffed female were used in the trapping process (and I have no reason to doubt this), it seems that males were specifically targeted - obviously because they are far more reliable like Fudgey says!
...sorry, I meant to say because they were presumably more likely to fit the size requirements!

[billybirder]

Is it also true that males and females can differ slightly in migration (or did I dream that one up??)

[shenk1]

The males are better at navigation so give a clearer idea of the true route taken, where-as the females always get lost and end up at the nearest shopping center for hours on end wandering around aimlessly

[RoyW]

Originally Posted by billybirder

Is it also true that males and females can differ slightly in migration (or did I dream that one up??)

This is known to be true for some species, a good example being the Chaffinch which was given the scientific species name 'coelebs' by Carl Linnaeus, the 18th century Swedish naturalist who is credited with coming up with the binomial naming system still used today.
'Coelebs', in Latin means single, or unmarried, and the name was given because flocks of this species in Sweden during the winter tend to consist largely of males, with the females migrating to milder cliimates further south or west.

Whether Cuckoos show any sex related differences in the timing or route of their migration is a different matter - we don't yet have enough information to answer this.

[RoyW]

Originally Posted by shenk1

The males are better at navigation so give a clearer idea of the true route taken, where-as the females always get lost and end up at the nearest shopping center for hours on end wandering around aimlessly

If certain regular contributors to the music thread see this you could potentially be in for a hard time!