Birds are shrinking in size because of global warming

Birds are getting smaller, and it’s one of the unexpected consequences of global warming…

Transcript

00:30Almost every one of these species has changed significantly through time and has gotten

00:43smaller.

00:45The reason behind this is that breeding ground temperatures have increased over the past

00:4940 years.

01:19And that's a complicated thing, but basically, as you get smaller, it's harder to make

01:49sure that you maintain your metabolic processes with the same efficiency.

01:53So the outcome of that is that smaller birds have a harder time migrating.

01:56And we think that this selection pressure has pushed these birds to become more efficient

02:02flyers.

02:03And one way to do that is through increases in wing length.

02:19And these are two sort of standard adaptive responses to climate change that we think

02:29may broadly facilitate persistence across species.

02:33However, if birds are changing their morphology just to maintain the status quo, it sort of

02:38calls their ability to adapt further, either through range shifts or changes in timing