title: Behaviorally Induced Camouflage: A New Mechanism of Avian Egg Protection.
abstract: When animals potentially occupy diverse microhabitats, how can camouflage be achieved? Here we combine descriptive and experimental methods to uncover a novel form of phenotypic plasticity in the camouflage of bird eggs that may be present in other avian taxa. Soil from the bare substrate adheres to the blue-footed booby's (Sula nebouxii's) pale eggs, which parents manipulate both under and on top of their webs. Analysis of digital images confirmed that dirtiness increases progressively during the first 16 days of the incubation period, making eggs more similar to the nest substrate. Observations of 3,668 single-egg clutches showed that the probability of egg loss declines progressively over the same time frame and then remains low for the rest of the 41-day incubation period. An experiment showed that when chicken eggs are soiled and exposed in artificial booby nests, they are less likely to be taken by Heermann's gulls (Larus heermanni) than clean eggs.
authors.affiliation: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, AP 70-275, 04510 Distrito Federal, Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Mayani-Parás
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Kilner
authors.forename: Mary Caswell
authors.initials: MC
authors.lastname: Stoddard
authors.forename: Cristina
authors.initials: C
authors.lastname: Rodríguez
authors.forename: Hugh
authors.initials: H
authors.lastname: Drummond
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D003116:Color; D017753:Ecosystem; D008800:Mexico; D009425:Nesting Behavior; D010063:Ovum; D010641:Phenotype; D011235:Predatory Behavior; D012987:Soil
chemical_list: D012987:Soil