Please note that the BTO (British Trust for Ornithology) carry out a brilliant Cuckoo tracking project.
We think that we need to be sure that we are clear how fledglings make the journey to their wintering grounds. As they have never been there before, how do they know how to get there?
If any of your birds are fledglings the tracks recorded are a really important refutation of some of the prevailing bird navigation theories where it is proposed fledglings fly on fixed compass headings.
We also know, that adults who have made the journey before use different navigation cues to fledglings (using two eyes, not one, for navigation) and also, typically like other species the journey home is not the same as the journey down to winter. Birds tend to dawdle on the route down to their wintering grounds stopping off for breaks and refuelling – feeding. On the way back to breed, they tend to go the fastest route to get the best breeding territories and mates.
Click for more fascinating data.