Saturday, August 3, 2013

The LANDSCAPE OF FEAR paradigm is at work in bird populations the same as it is in the world of mammals...............When Owls are in the "neighborhood" and advertise their presence through their "hooting", songbirds tone down their own "singing" to avoid being an Owl late night snack..............Texas Tech researchers conducted their research in the Cary Institute Forest in Millbrook New York where the Veery(Thrush) reduced their singing sprees for up to 30 minutes when aware that Barred Owls were in their domain.....................Like John Laundre found studying Elk and their reactions to the presence of Wolves and Pumas, there likely is some sort of cost/benefit condition that the Veery's go through in the presence of Owls.................Does reducing their singing keep them alive but reduce their chances for finding a mate or defending their territory from other Veery's?.

Veeries Very Quiet When Owls Are About

science daily— Study shows birds eavesdrop on owls and change their dusk singing patterns to avoid becoming potential prey


If you hear an owl hooting at dusk, don't expect to catch the flute-like song of a Veery nearby. This North American thrush has probably also heard the hoots, and is singing much less to ensure that it does not become an owl's next meal.

Research by Kenneth Schmidt of Texas Tech University and Kara Loeb Belinsky of Arcadia University in the US, published in Springer's journal Behavioral Ecology and Sociobiology, provides insights into just how eavesdropping between predators and prey around dusk may be shaping communication in birds.. The study is the first to use the playback of recorded owl vocalization at sunset to study how birds change their behavior when potential predators are heard nearby.

Perching birds are generally more exposed during periods of extended singing. They are less vigilant and their song can often attract the attention of a predator to their fixed location. Despite this risk, dawn and dusk chorusing is a common trait. One such perching bird is the Veery (Catharus fuscescens), a common small brown and white thrush that is most active during the day. Its most common call is a harsh, descending "vee-er," from which the bird gets its name. This particularly vocal bird has a breezy, flute-like song, a pronounced dusk chorus and is often heard singing well after sunset.. This behavior could potentially expose the bird to predation.

Veery and Barred Owl



The study was done on the forested property of the Cary Institute of Ecosystem Studies in Millbrook, New York, where up to three pairs of barred owls live. This owl species is known to be a predator of Veeries. The researchers found that the Veeries reduced their singing patterns for up to 30 minutes after recorded owl sounds were played. The songbirds also displayed fewer extended singing bouts at dusk and stopped singing much earlier in the evening.

"Singing becomes much more risky in the low light of dusk when owls are around," explains Schmidt. "However, by eavesdropping on owls, Veeries can adapt their singing behavior to decrease the risk of predation."

Schmidt adds that the study of the avian dusk chorus has been largely ignored relative to the more well-researched dawn chorus. "Further studies of dusk chorus singing may reveal how the risk of being attacked by predators has contributed to the evolution of singing behavior at dusk," he believes.

No comments:

Post a Comment