Swallow Migration

[Barks]

Apologies if this sounds really stupid but we were in Berlin last weekend having an evening beer and watching Swallows screaming around the sky just like they do in UK and I wondered why UK Swallows go the extra couple of hundred miles when it would be less effort to roost in Europe

It can't just be the scenery can it?

TIA

[Buenchico]

If you've flown all the way from South Africa (as our swallows do) going across the Channel to get to the best food reserves (and slightly cooler temperatures which might be better for bringing up fledglings without the risk of them becoming dehydrated) is probably worth the effort.

Remember that young birds, still in the nest, can't get anything to drink; they have to get their fluid intake from the food provided to them by their parents. So those parents won't want to nest where there's any significant chance of a heatwave in spring or early summer.

http://www.gardenbird.co.uk/migration-map

[Svejk]

well for a start, Berlin is north of half of England, but it is an interesting question. Why go to, say, Inverness(if they do) instead of settling down in Guernsey. Are they like fish and always go back from whence they were born/raised?

[Milvus]

Buenchico and Svejk both have good points. Certainly adult swallows return to nesting sites. Ospreys adult and young return to the same sites. A further thing drives Northern migration and that is the length of daylight. The further North the longer the day, the longer the adults have to feed their young. Balance the distance North with the amount of insect life and that is where the optimum nesting sites will be

[brainiac]

The birds you saw "screaming round the sky" were swifts, not swallows!

[jomifl]

^ and they can be *** loud.

[Barks]

Sorry for the late reply but thanks to everyone, I did wonder if there was a "spawning salmon" element to it but I like the idea of a Goldilocks zone of temperature, daylight and insect abundance
I didn't take into account the fact that Berlin is roughly the same latitude as Birmingham and I didn't know it was only Swifts that scream so I count this as a three-for-one deal

Thanks once again