Dear Readers, with Valentine’s Day coming up tomorrow, my thoughts turned (as they do) to sexual dimorphism in birds. Why is it that in some species (like the Mallards in the photo above) the male and female look completely different, while in others (like most geese) the sexes look identical? One theory is that this relates, in part at least, to the male’s ‘fitness’, and in particular his parasite load – if the male is beautifully coloured, chances are that he’s also healthy. And females clearly tend to choose the healthiest males. In species where the males play no part in rearing the offspring, they can afford to be highly ornamented, but the differences might be toned down where, as in many song birds, the males are essential to the survival of the chicks. Also, in some birds the sexes look identical but have complex breeding displays (such as those of many grebes) which will also show how fit the ‘dancers’ are. In short it’s a very complex area, and I’m sure for all species there is an intricate balance to be calculated between survival of the individual, and the passing on of genes. Let me know if you have any theories! I am just starting to feel well enough to exercise my brain again.
Now, to the quiz. Here are some female birds that look very different from their male counterparts, but what species are they? Just choose the name of the bird from the list below and match to the photo. So, if you think the bird in Photo A is a chaffinch, your answer is 1)A. I have chosen just two groups, songbirds and raptors, but I think this is mega-tricky (and after me promising to be kind this week too). Let’s see how we all get on.
All answers in the comments by 5 p.m. UK time on Friday 18th February please, and the results will be posted on Saturday 19th February. I will disappear your answers as soon as WordPress is kind enough to let me know about them (or probably sooner as they have been remarkably tardy just lately).
- Chaffinch (Fringilla coelebs)
- House sparrow (Passer domesticus)
- Siskin (Carduelis spinus)
- Greenfinch (Chloris chloris)
- Blackcap (Sylvia atricapilla)
- Redstart (Phoenicurus phoenicurus)
- Pied Flycatcher (Ficedula hypoleuca)
- Sparrowhawk (Accipter nisus)
- Common Kestrel (Falco tinnunculus)
- Merlin (Falco columbarius)