About us: We own two Wild Birds Unlimited nature shops in East Lansing & Okemos, Michigan
that provide a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Sunday, May 31, 2009

Are birds getting bigger?

I know the statistics show Americans have become larger over the years. So as I watch the Starlings feeding huge babies, I’m wondering if birds are getting bigger too. P.

What a thought provoking question? As most dinosaurs would tell us (if they weren’t extinct), there is evidence that being big can be bad for surviving. Being small has long been thought to help things survive extinction by having larger populations, greater genetic variation, shorter time to maturity, and fewer resources to suvive.

In a study done by paleontologists on a collection of bird ancestor bones approximately 65.5 million years old, it was found that there was a general increase in size for the birds in three of the four families. The big point of interest is the Ornithuromorpha, the last of these four families, got smaller over time and is the only family of birds who have members that managed to survive the Cretaceous–Tertiary extinction event.

So as Americans get bigger and stronger to conquer…everything in their way, I believe birds find their niche in the world…small and have the best chance at survival if they stay small.

I couldn’t find any recent study on the size of birds, but based on observations of birds from the 1800’s to the present there is no obvious change in birds’ size unless helped along by farming practices.

Keep the questions coming and I’ll answer them as best I can. You can also chime in if I get something wrong.

Source: The DinoBase Public Forum
http://dinobase.gly.bris.ac.uk/forum/viewtopic.php?id=538
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Posted by: http://lansing.wbu.com/ Wild Birds Unlimited Mid-Michigan

1 comments:

  1. Since I wrote this blog Science Daily has an update:

    In a forthcoming article in PLoS Biology, Sievert Rohwer, and his colleagues at the Burke Museum at the University of Washington, provide evidence that maximum body size in birds is constrained by the amount of time it takes to replace the flight feathers during molt.

    As bird size increases, feather growth rate fails to keep up with feather length until, eventually; feathers wear out before they can be replaced. This fundamental relationship requires basic changes in the molt strategy as size increases, ultimately limiting the size of flying birds.

    To read more of the article go to: http://www.sciencedaily.com/releases/2009/06/090615203056.htm

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