Older cranes teach new routes to young birds, researchers find

Published 1:30 am Sunday, September 11, 2016

Yes, older can be wiser, at least among whooping cranes.

In response to climate and land-use change, a re-introduced group of cranes is changing its migration patterns led by older, more experienced cranes.

Researchers at several institutes and universities, the U.S. Geological Survey and the International Crane Foundation investigated a behavior known as “shortstopping,” the shortening of a migration route by shifting wintering grounds in the eastern U.S. toward breeding grounds in Canada.

This allows the birds to spend less energy and be at the breeding grounds sooner but requires them to find new, closer overwintering sites. Warmer temperatures have allowed them to winter farther north.

Researchers found that the first cranes to use new sites were older birds.

“For each additional year of age of the oldest bird in the group, the distance between breeding and wintering grounds was reduced by … almost 25 miles,” said researcher Claire Teitelbaum. “Older birds often chose overwintering sites which they were familiar with from previous migrations.”

The locations appear to have been taught to younger birds. In 2006, no 1-year-old birds shortstopped, but by 2015, 75 percent of them did so, according to the study.

Shortstopping in the re-introduced population occurs to a vastly greater degree than in the remnant wild population, which migrates between northern Canada and the Gulf coast of Texas.

Bird spotting: A rare sighting of a great egret occurred at the Edmonds marsh on Aug. 31, the third sighting of this species. The first sighting was at the marsh in April 2004 and the second was a flyby in the Edmonds bowl, according to Carol Riddell.

Nineteen species of shorebirds recently were sighted on Fir Island while Ryan Merrill was walking the Jensen access and the Skagit game range. Shorebirds included a whimbrel, about 500 least sandpipers and 700 Western sandpipers, about 35 shore- and long-billed dowitchers, more than 50 greater and less yellowlegs, and a half-dozen Wilson’s snipes.

Larry Schwitters has been keeping track of Vaux’s swifts into the chimney on Wagner Elementary School in Monroe. During the week that overlaps the end of August and beginning of September, the communal roosting site had hosted more than 60,000 roosting swifts.

Washington state has four important Vaux’s swifts roosting sites of global significance, according to Schwitters: old Northern State Hospital in Sedro-Woolley, Monroe’s Wagner School, the old schoolhouse in Selleck and building 2068 at Joint Base Lewis-McChord.

A Bird in Hand: This program is a special event by the Whidbey Audubon Society and a chance to see the Whidbey Audubon bird specimen collection, 12-3 p.m. Sept. 18 at the Bayview Farm and Garden, 2780 Marshview Ave., just off S.R. 525 near Langley.

Tables in the greenhouse will be staffed by volunteer bird experts who can answer questions about the museum-quality specimens.

The collection makes an appearance every other year.

Bird brain: Vanderbilt researchers have conducted the first study to systematically measure the number of neurons in the brains of more than two dozen species of birds ranging in size from the tiny zebra finch to the 6-foot tall emu.

The researchers found that bird brains consistently have more neurons crammed into their small brains than are stuffed into small and mid-sized primate brains of the same mass.

This may provide the “how” of why some birds, such as crows, can solve problems, and manufacture and use tools and recognize themselves in a mirror, qualities that once were attributed only to primates.

Because of the large amount of neurons in a densely packed area, birds have high cognitive functions.

Columnist Sharon Wootton can be reached at 360-468-3964.