Study: Chicks still in eggs sense outside

Posted on Jul 12, 2012 in Science | 0 comments

Researchers in North Dakota say they’ve discovered some bird chicks can sense day length even while still in the egg, which in turn affects how they develop.

North Dakota State University’s Mark E. Clark and Wendy Reed said their study showed embryos in eggs appear to sense external environments and adjust how they develop.

The researchers studied the Franklin’s gull, a bird that migrates long distances and requires precise timing to arrive at prairie wetlands of North America to nest in large colonies come springtime.

Inside the gulls’ green-and-black speckled eggs, the developing chicks also sense spring days, the researchers said.

“The growing embryos integrate signals from the nutrients provided to eggs by mothers with the amount of daylight,” Clark said in an NDSU release Tuesday.

“The signals let the chick know whether the egg was laid at the beginning, or at the end of the nesting period.”

Chicks from eggs produced at the beginning of nesting take longer to hatch but are larger than chicks from eggs laid at the end of nesting which hatch in less time but at a smaller size.

“Chicks hatching later in the season have less time to grow, less time to become independent, and less time for flying lessons before they must migrate to South America in the fall,” Reed said.

Embryos in late season eggs appear to be sensing external environments and adjusting their development, which may be important for chicks to successfully migrate, Clark said.

Copyright 2012 by United Press International