Why do Sandhills Breed so far North?
May 16, 2001 - At the NJ State Showcase, Signals was being presented by the Ann Street
School (Newark, NJ). A question from the audience of administrators and
teachers was:
'Why do SAndhill Crane breed (nest/give birth to their young) so far North
in Canada and Siberia? Why don't they just stop and breed in the U.S.?
Dr. Gary Krapu, of the Northern Prairie Wildlife Research Center
(USGS)(TARA: LINK TO PARTNER PAGE for NPWRC) responds:
"I will try to answer the question. First, sandhill cranes breed from Cuba
to arctic islands so some do stay in much warmer climates to nest. Lesser
Sandhill Cranes which breed in the far north appear to have evolved in the
arctic and possess adaptations allowing them to breed successfully there
despite the harsh climate.
"During the last ice age, parts of northern Alaska and northeastern Russia
were not covered by ice and thus cranes were able to survive when vast
areas were covered with thick ice sheets. Lesser Sandhills are much smaller
than Greaters which nest in temperate regions so require much less energy
to survive in the cooler and probably less
productive environment.
"Small body size also allows the young to fly earlier which is important
because winter comes much earlier the arctic and any bird that can't fly
before freezing conditions arrive is "toast" so to speak. Cranes, like many
other species of birds home back to the same
areas where they were hatched.
"We don't understand the mechanisms well
that allow birds to find their way back home but in some cases it probably
is learned and in others it likely is hardwired into their genetic makeup."
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