Science briefs: Birds race to mating grounds because of global warming, arrive exhausted

Shifting environmental signals are making the birds race northward on their spring migration, flying faster and skipping the stops they normally use to rest and refuel, said a study in the journal Current Biology.

The finding gives new insight into the way climate change is altering the calculus of animal migration. "This is the first one I know of where a long distance migrant is increasing its travel speed," said Matthew Ayres, a biology professor at Dartmouth.

Barnacle geese spend their summers in the Arctic, where warmer temperatures transform the snowy landscape into an all-you-can-eat buffet of grasses, roots and mosses. As days grow longer in spring, the geese take sunlight as a cue to head north. The goal is to arrive early enough to take advantage of the tender spring greens that are especially beneficial for chicks.

But as human-caused climate change shifts weather patterns, spring arrives earlier some years. The birds don't know that — only realizing that spring has arrived by seeing environmental cues along the way. They try to make up the ground, rebuilding their strength when they arrive. But that means nesting is delayed and chicks are born when the food supply is past its prime.

A baby's cry might tell you something about how its voice will sound decades later as an adult. Research has shown that how we sound as adults may be determined before puberty. But when do our voices start emerging?

New research — published in the journal Biology Letters — indicates that the pitch of babies' cries at 4 months old may predict the pitch of their speech at age 5. In fact, the researchers said, the differences identifiable in babies' whines can explain 41 percent of the differences in voice pitch that appear by age 5.

Taken together with previous studies, they said, this suggests a discovery that may be surprising: that "a substantial proportion" of the difference between how we sound in adulthood may be traceable back to the time we spend in utero.

News services