California
brown pelicans completely failed to breed at their nesting sites in Mexico this
year, surveys have found. Scientists are reluctant to blame any one cause for
the drastic decline in fuzzy-headed baby pelicans, but a similar drop in
breeding numbers struck during previous El Niño events.
Overfishing
of sardines and habitat loss could also be hurting the pelican population. But
this year is the biggest drop in baby pelicans seen in nearly five decades. Scientists have yet to officially
declare an El Niño, but forecasts call for a 78 percent chance of the climatic
event occurring by summer.
The pelicans' behaviour this year suggests they're already responding to
the developing El Niño.
How warm water hurts baby birds:
An El Niño is a natural climate cycle that displaces cool water in the
Eastern Pacific Ocean with warmer water, which disrupts fish populations.
During previous El Niño years, brown pelicans trailed their shifting food
supply, flocking to more northerly fishing grounds earlier than usual, studies
found. Their food migrates, and so
they need to track their food.
However, more research is needed to link this year's decline to El Niño.
For example, while El Nino conditions favour a boom in sardine populations,
anchovies are at a low point in their natural cycle, and the oily fish is a
favorite food for breeding brown pelicans.
(www.livescience.com)
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