Earlier bird migration

An interesting study by University of East Anglia (and University of Iceland, Tomas G Gunnarsson) found that individual (adult) birds are not migrating earlier, rather, since they nest earlier, the young birds migrate earlier.

So warming climate is allowing the birds to nest and hatching earlier, which results in those younger birds arriving earlier – but apparently, each individual bird will stick to a fixed date for migration.

Or, as it says in the news item:

We found that birds hatched in the late 1990s arrived in May, but those hatched in more recent years are tending to arrive in April. So the arrival dates are advancing because the new youngsters are migrating earlier.

This was found by studying the Icelandic black-tailed godwits over 20 years.

About this study on Eurekalert.com.