On the horizon

A hot problem for expectant titmice

A mother bird needs to check the temperature, not the calendar, if she wants more of her nestlings to survive in a warming world. That's the conclusion a team of Dutch and British scientists have drawn after studying a population of great titmice in one of the Netherlands' largest national parks. One goal was to see if females shifted their reproductive schedule to match climate-driven changes in the hatchlings' food supply: caterpillars. As the climate has warmed, the insects have turned into butterflies earlier, leaving fewer caterpillars for newborn great titmice to eat.

Most of the females in the study group failed to adjust their mating schedules. The offspring of the handful that did were twice as likely to survive. A genetic component in the latter group could help the birds survive global warming.

Less clear, the team says, is whether the pace of adaptation in birds will match that of climate change. The results appear in the current issue of the journal Science.

A visit to the beach some 160 million years ago would have been a dangerous outing, if new fossil tracks found in Wyoming are any indication.

A group of scientists has found several sets of tracks belonging to an ostrich-size dinosaur that, like the ostrich, traveled on two legs. The tracks, which appear at several sites in the northern part of the state, date to between 165 million and 167 million years ago.

The team, led by Debra Mickelson of the University of Colorado, says the creature most likely swam and waded along the shore of an ancient sea that once covered much of the US West. The team described how the footprints gradually became shallower, suggesting that the creature grew more buoyant as it waded into deeper water.

The team, which reported its results this week at the Geological Society of America's annual meeting in Salt Lake City, notes that similar footprints have been found in other parts of the world. But its findings represent the first evidence that such creatures roamed what is now Wyoming during the Jurassic period.

For 45 years, marine scientists have searched in vain off Mexico's Pacific coast to pinpoint a mother lode of undersea "popcorn" - volcanic rocks that explode when brought to the surface. Now they've found it some 200 miles south of San Diego near the island of Guadeloupe, dubbing the undersea location "Popcorn Ridge."

The rocks explode because the gases they contain no longer are held captive by the intense pressure at the sea floor. Scientists prize these rocks because they promise to yield information on the gases in Earth's mantle. The Popcorn Ridge samples seem to be anywhere from a few centuries to a few decades old, younger than other samples taken elsewhere.