Visitor Counter

hitwebcounter web counter
Visitors Since Blog Created in March 2010

Click Below to:

Add Blog to Favorites

Grizzly bears, black bears, wolves, coyotes, cougars/ mountain lions,bobcats, wolverines, lynx, foxes, fishers and martens are the suite of carnivores that originally inhabited North America after the Pleistocene extinctions. This site invites research, commentary, point/counterpoint on that suite of native animals (predator and prey) that inhabited The Americas circa 1500-at the initial point of European exploration and subsequent colonization. Landscape ecology, journal accounts of explorers and frontiersmen, genetic evaluations of museum animals, peer reviewed 20th and 21st century research on various aspects of our "Wild America" as well as subjective commentary from expert and layman alike. All of the above being revealed and discussed with the underlying goal of one day seeing our Continent rewilded.....Where big enough swaths of open space exist with connective corridors to other large forest, meadow, mountain, valley, prairie, desert and chaparral wildlands.....Thereby enabling all of our historic fauna, including man, to live in a sustainable and healthy environment. - Blogger Rick

Subscribe via email to get updates

Enter your email address:

Receive New Posting Alerts

(A Maximum of One Alert Per Day)

Wednesday, December 2, 2015

Can species really re-adjust their breeding cycles to sync with Spring leaf out as climate change brings Spring earlier and earlier every year?..........Over a 25 year research study in New Hampshire, the Back-Throated Blue Warbler has demonstrated an ability to initiate their clutches up to 6 days earlier than "leaf-out".........The Darthmouth College researchers involved with these observations are not certain as to why the birds can exhibit this flexibility...........Theories include visual cues or psychological sensitivities to forest surroundings being what sets off early breeding..............Important to note that as warming continues, it is felt strongly that the birds will not be able to continually "get-out-in-front" of leaf green out,,,,,,,,,,,,a dire message to us all that increasing biodiversity "sinks" are likely to ensue as the planet's temperatures leap to pre historic levels

Warbler Species Adjusts to Early Springs

By Dana Kobilinsky

A male black-throated blue feeding nestlings. Image Credit: NL Rodenhouse
Many wildlife species are feeling the impact of climate change, but one bird species seems to be having somewhat of an easier time adjusting.
In a recent study published in the journal Oikos, researchers found that black-throated blue warblers (Setophaga caerulescens) are able to adjust the time that they breed based on when spring leaf expansion occurs.
For example, when spring came 10 days earlier than expected, the birds initiated their clutches five or six says earlier, according to lead author of the study Nina Lany, who completed the study as part of her PhD dissertation at Dartmouth College. “They didn’t match leaf expansion exactly, but they adjusted the timing of breeding by an appropriate amount,” she said. However, Lany added that this flexibility could have limits as a warming climate continues because the date these migratory warblers arrive on the breeding grounds is relatively inflexible.
As part of their study, the researchers used 25 years of demographic measurements of the birds in the Hubbard Brook Experimental Forest in New Hampshire and compared their breeding time with the presence of caterpillar prey and the plants that caterpillars feed on. They found that there was no consistently timed food peak in the forest, perhaps because a diversity of caterpillar species feed at different times throughout the birds’ breeding season. “There was really no way for the birds to time breeding so peak food demand for their nestlings coincided with peak food availability,” she said. “It wasn’t predictable.”
But the researchers observed that the timing of the warblers’ first clutches had a strong link to spring leaf expansion. This might be due to visual cues or a physiological sensitivity to changes in temperatures, but Lany said they’re not entirely sure how the birds are able to exhibit this breeding flexibility.
Lany added that the length of the interval between when the birds arrive and initiate their first clutches is short in early springs. “With continued warming, birds wouldn’t arrive in time for breeding at the appropriate time. From a conservation point of view, this is an important take home message,” she said.
Dana Kobilinsky is an associate science writer at The Wildlife Society.Contact her at with any questions or comments about her article. You can follow her on Twitter at @danasaur92.

No comments: