A BIOLOGIST COMMENTS

After reading Joe Duff’s Field Journal posting of January 29th we received this thoughtful comment, and asked the author for permission to share it with our website readership.

I am biologist in southern Indiana, and although I’m not an ornithologist, I do subscribe to the bird lists here. As you are aware and have reported, we have an unusual number of cranes, both Sandhill and Whooping, that just haven’t migrated beyond Indiana this year. There are other migratory bird species staying in larger than normal numbers as well.

The weather has been mild, with the grass still green and the ground unfrozen. Some early spring flowers are blooming more than a month early. Now the sun feels stronger, with day length increasing.

As Joe said, the signals for stopping and starting migration are not completely known, but I would be surprised if the birds that have spent the winter here [in Indiana] migrated much further now, even if the weather becomes more winter-like for the next month or two. Are they done going south, and is this as far as they got? So your group of Whoopers may just be joining the bird herd this year, much to everyone’s frustration.

It is good that cranes are so flexible with migration patterns, since over their millions of years as species they have seen ice ages come and go, and who knows what else – climate changes that are on par with the one we’re inducing, surely. Timely adaptation to such changes must be part of their repertoire. Even if they never get to Florida this spring, they will be flexible enough to find Florida on their own in a future migration, right? We hope?

When I was a graduate student in the mid-1970s I had the privilege to hear the famous biologist and bird researcher William T. Keeton talk about his work on homing in pigeons.

He said (something close to), “What a bird CAN do and what it WILL do are two different things.” He said people thought pigeons couldn’t find their way home when it was overcast, but in fact they just didn’t like to fly then. He trained them to fly on overcast days, and discovered that could home just fine, and then studied how they navigated without the sun, defying decades of research by others. http://www.pnas.org/content/85/13/4907.full.pdf

Birds do what they will, thank goodness – we certainly aren’t smart enough to make all the “right” decisions for them. Knowing when to follow their lead is tricky when you’ve been training them so meticulously to follow yours. Sounds as if you’ve reached that point.

Thanks again for all your heroic work helping the Whoopers hang onto this world, hopefully for a few million more years to come.     – M.C

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