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Monday, February 8, 2016

Corvid Course - Class #2 Steller's Jays & Communication

Our 2016 "Conservation Course" started January 25th.  Below are short-hand notes taken by Raechel Youngberg and a video by CJ Peterson, both class participants.  To see the notes and video from the first class click here

Class #2 - Steller's Jays & Communication with Alexis Billings
February 1, 2016

Watch and listen to most of the class on this video (we had a problem recording the first part of the lecture; this video starts late.)

Alexis says she studies "bioaccoustics" - sounds that living things make

Jays are spread throughout the phylogentic (aka evolutionary) tree and there is not one overall characteristic of what makes a jay a jay.

Boreal jays (gray jays etc), ground jays and old world jays are not in the same genus as scrub jays, steller & blue jays, pinyon jays etc.

Gray Jay (Perisoeus canadensis)
Gray jay by Mary Kiesau
-Boreal forests
-We are southern range of their territory
-do not migrate
-make long term pair bonds, and are socially monogamous
-one of the few corvids that has something that sounds like a song, the “whisper” song
-breeding starts in February
-they are a semi-cooperative breeder: family groups work together to raise young but helpers are not allowed to feed the chick until it becomes a fledgling
-cache food under bark using special sticky saliva

Steller's Jay (Cyanocitta stelleri)
Steller's jay by Mary Kiesau
-Named by George Wilheim Steller, a German who worked for Russia and who is considered a pioneer of Alaskan Natural History
-Black, gray or blue chest, head and upper back and breast
-Blue body w/ black on feathers
-Lots of variation between subspecies and hybrids (our local subspecies is Cyancitta stelleri annecterns)
-Sexually dimorphic(males and females are different)
-males slightly larger with slightly longer tails

-males are much more colorful than females in UV spectrum (we can't see it but the birds can)
-sex specific calls (creek call = males only, rattle call = females only)
-the are western coniferous forest birds
-subspecies can interbreed, though they have slightly different genetics, and they can vary in size, coloration, habitat range

Our local Steller's jay is Cyanocitta stelleri annectern
-Forehead has small light blue streaks
-white eye area
-paler than Cyanocitta stelleri (especially on belly)

-begins in March-April with sexual sidling and courtship circling
-culminated courtship feeding

Pair Bonds:
-long term pair bonds
-not sexually monogamous
-often stay with mate outside of breeding season

-Nest site selected by both pairs and built by both pairs
-horizontal brances close to truck between ground level and 30m high
-bulky structure of plant material, sticks, leaves and mud (one of only two corvid species known to use mud)

Photo by Jim Peaco, NPS
-blueish gray with brown freckles
-slightly glossy
-average 3 to a clutch
-16 days incubation

-Altrichial young (young need assistance from parents after birth)
-remain in nest for 16 days after hatching
-once fledged they beg for food for one month before parents stop feeding them
-may stay with parents for fall and winter

-diet primarily consists of anthropods, nuts, seeds, berries, small vertebrates

Places they forage:
-ground, bushes, trees
-fly catch
-forage under loose bark
-Also help spread seeds of white bark pine
-cache food in trees and ground
-eat snow and ice even when water is abundant
-nest raiders and eat young of other birds

-flight: strong & deliberate
-accomplished hoppers
-expressive crest (stands taller when stressed)
-use wings, tail feathers for posturing in conflict and courting behavior

Intelligence is displayed by:
-problem solving
-spatial memory
-self awareness
-use of tools
-complex social interactions

Predation and anti-predation behavior:
-give alarm calls as responses to danger
-display mobbing behavior (attack predator)

Sharp-shinned hawk by Mary Kiesau
-Northern Pygmy Owl
-Sharp-Shinned Hawk
-Red-Tail Hawk
-Northern Goshawk

Study used visual and acoustic cues to see how Steller's jays reacted to the four predators
-Size is not everything
-Hunting strategy counts (sharp-shinned hawks are quicker and more agile than red-tailed hawks)
-No distinct difference between visual and acoustic cues

Alexis predicted that size would be the biggest factor in the Steller's jays reactions to the cues. But a variety of factors influenced the result (see above). Alexis predicted that the jays would have the most significant vocalizations and mobbing attacks towards Northern Goshawks but it turned out that Sharp-Shinned Hawks and Northern Goshawks elicited similar results.

When the jays heard red-tailed hawks calls they responded by mimicking their calls which may act as a warning system for other jays nearby.

Alexis also is studying how animals of different species communicate in a forest setting. She found that other birds (and even squirrels!) listen to red-breasted nuthatches for warnings about their environment. She also found that black-capped chickadees are not considered reliable and are not listened to. It seems that Steller's jays are only listened to by other Steller's jays.

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