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Social Behavior
-- includes nonbreeding and breeding activities
-- how birds interact with each other, space themselves,and maintain high fitness and survival
-- feeding flocks common, especially in winter
-- allow greater protection from predators, facilitates foodgathering, saves energy from trying to keepindividual territories
-- some examples previously given: Harris’ Hawk, WesternGull and gull ‘gangs’, Double-crested cormorantsswimming in formation to herd schools of fish
Blackbirds, including starlings, red-winged blackbird, and gracklesare well known for their huge winter flocks that can number in thehundreds of thousands
Mixed species feeding flocks also common in winter
-- provides greater protection to all individuals
-- each species knows each others’ alarm calls
-- can form for just an hour or the day
-- may learn new foraging strategies by watching others
-- no interspecific competition for food as each species hasits own niche (e.g., warblers, chickadees, titmice,and woodpeckers feeding and moving together)
-- seabird feeding flocks with diving, dipping behaviors among different species
Roosting flocks also possible
-- birds forage individually in day, flock together at onesite for night
-- crows and ravens, vultures, ibis, herons, blackbirds, gullsand some shorebirds especially known for this
-- many advantages:
1. Predator avoidance/protection2. Thermoregulation3. Information exchange4. Develop pair bonds
naturalmoment.com
Roost cavities become important for thermoregulation at night in winter
Record roost for pygmy nuthatch in Flagstaff, AZ, winter 1981-82
10 winter social groups converged on one cavity from as far awayas 1.7 km, total in cavity was 167, most ever recorded
Gull ‘clubs’
Breeding and non-breeding season, gather at dusk or hang outall day
Non-breeders may establish pair bonds here, mate for life, practicebuilding nests, and build social skills
Behavioral Ecology in Birds
Field pioneered by Konrad Lorenz and Niko Tinbergen,1950s and 60s
Set foundation for modern behavioral studies
Lorenz (1903-1989) was an Austrian ornithologist
Famous for work on imprinting behavior in Greylag Geese
Lorenz is considered the ‘father of ethology’, or study of animal behavior
Besides research on imprinting behavior, also studied innate behavior and ‘fixed action patterns’
e.g., gull chicks always respond to red dot on adult bill by begging for food, pecking on spot to stimulate regurgitation of food by adult
Used models to illustrate how the behavior is innate
Greylag goose and FAP
Niko Tinbergen (Dutch ornithologist, 1907-1988)
Studied behavior of Herring Gulls
Proposed that any behavior should be examined in terms of causation, ontogeny, adaptation, and phylogeny
Shared 1973 Nobel Prize with Konrad Lorenz and Karl von Frisch
Causation
• Internal factors– Hormonal– Physiological
• External factors– Changes in season,
photoperiod impacting hormones and behavior
Ontogeny• Studying how individual behaviors develop
– Innate vs. learned
• “Double-scratch” of New World sparrows– Rapid backwards kick performed with both feet to
clear superficial layer of the surface (feeding)– Innate--appears in isolated and hand-raised birds
• Environmental influence on learned behaviors
http://eema-le.blogspot.com/2009_04_01_archive.html
Adaptation• How behavior functions for:
– Survival– Improving fitness– Reproductive success
e.g., winter attendance in
murres and gulls
Habituation to save energy
Phylogeny• Behaviors can be inherited or innate (passed on
from generation to generation)• Become characters for determining phylogenetic
relationships– Courtship displays (Stereotyped movements &
vocalizations)– Urohydrosis (Ciconiiformes)
http://www.calacademy.org/blogs/rainforest/?p=620
Innate behavior• Behaviors that require no learning, are
genetically controlled• Simple reflex behavior and fixed action patterns• Feeding and begging behaviors
– Gulls chicks peck at red spot on adult bill– Making begging calls when adult returns to nest
• Desire to incubate eggs– Common murre, penguins
Learned behavior• Opposite of innate• Young or adult birds watching other
adults and mimicking• Learn new skills for foraging,
defense, etc.• Classic example: Titmice in England
and milk bottles– at least 11 species of birds learned this
behavior within 10 years
http://www.corbisimages.com/stock-photo/rights-managed/FL003273/blue-tit-drinking-from-milk-bottle
Studying animal behavior
• Blind observations– See large part of colony– Sit comfortably without disturbing birds
• Establish methods for systematic observations• Quantify results from counting and coding
observations
Penguin predation study• Research questions:
– Are birds on the edge more susceptible to predation?
– Do predators vary their activities with time of day and season?