Spring is Arriving Earlier, Messing With Bird Migrations

By Roni Dengler | September 12, 2018 1:30 pm
migrating whooping cranes hunt for food in water

A pair of whooping cranes look for food at Necedah National Wildlife Refuge in Wisconsin. A new study shows that migrating birds could suffer as climate change shift the onset of spring. (Credit: critterbiz/shutterstock)

Thanks to climate change, spring now comes earlier. But how much sooner the season arrives varies across the U.S. That’s according to a new study published Wednesday in the journal PLOS ONE that assessed the first appearance of leaves and flowers in nearly 500 U.S. National Wildlife Refuges over more than 100 years. 

Researchers found the irregular seasonal changes affect migratory birds’ breeding sites, an outcome that could endanger many species.

Global Travels

Hundreds of migratory birds travel thousands of miles across the U.S. each year. Many birds move from Central America, where they spend the winter, to locations across the northern U.S. to breed and raise young. The success of their international travels depends on good timing. The birds must coordinate their arrivals with spring’s appearance to ensure enough food is available to eat at their destination.

Though some birds have adjusted when they migrate, it’s still unclear whether they’ll be able to keep up with changes in food availability across such vast distances over the long-term.

Eric Waller, a physical scientist at the Western Geographic Science Center of the United States Geological Survey in Menlo Park, California, who led the new research, wanted to know how the timing of the beginning of spring has changed over the last century and whether differences might affect migratory birds.

Speeding Into Spring

So, the researchers mapped data of first leaf and first bloom appearances, indices that mark the onset of spring, across 496 national wildlife refuges in the U.S. stretching back to the beginning of the last century. They found that spring now starts earlier — with leaves budding up to 3 days sooner each decade — in 76 percent of the wildlife refuges.

When the team compared the change of spring’s arrival to North American bird flyway paths, they found spring arrived a quarter of a day earlier each decade along the Central migratory route, but nearly half a day earlier each decade along the Atlantic path. Spring also came sooner at more northern latitudes, which could impact when food is available for birds along their migratory paths. So researchers assessed how a premature spring might affect blue-winged warblers and whooping cranes, two bird species that use distinct habitats and migratory pathways.

Susceptible Species

“When considering breeding and non-breeding habitats of migratory birds — such as the whooping crane and blue-winged warbler — continental-scale shifts in the onset of spring have species- and flyway-specific ramifications,” Waller said in a statement.

Waller and colleagues found spring came nearly half a day earlier each decade at both birds’ breeding sites, but not where they spent their winters. That means they may arrive at breeding sites after insects and other grub are at their most abundant.

CATEGORIZED UNDER: Environment, top posts
MORE ABOUT: climate change
  • https://sites.google.com/site/deanjackson60/home Dean Jackson

    There is no such phenomena today called ‘climate change’, and CO2, being a heavier/denser molecule than either N2 or O2, which informs us that N2 and O2 carry more heat than CO2(!), displaces greater heat retaining N2 and O2 molecules, thereby COOLING the area of the displacement. Ah, now I’ve awakened you to actual physics. So what is heating the atmosphere, you ask? The massive increase of man-made structures on the ground the last seventy years, structures whose heat readings are intentionally minimized by the placement of heat monitors in relatively cool parks!

    The Actual Physics and Chemistry of Nitrogen, Oxygen and Carbon Dioxide

    CO2 is a denser molecule than either N2 and O2 – one-third denser due to one-third less heat contained in the CO2 molecule – which informs us that CO2 COOLS the atmosphere by displacing greater heat retaining N2 and O2 molecules. CO2 has always been known to be a cooling molecule, primarily due to its use by agricultural engineers to increase crop yields and noticing concomitant temperature drops. This informs us that man is mediating the atmosphere, not changing it, because the real culprit for the heating of the atmosphere is the massive increase of man made structures on the ground that act as heat sinks while also decreasing the cooling effect of vegetation at night. If one desires less heat, which would mean a less temperate atmosphere that decreases crops and increases weather related deaths, the mechanism to be used is to INCREASE CO2 levels, not decrease those levels. Increases of CO2 into the atmosphere actually tempers the current warming of the planet. Note: ‘Climate change’ frauds naturally remain silent regarding the heat generated by man made structures on the ground.

    My blog…

    Google: djdnotice blogspot


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