Factors affecting individual variation in nestdefense intensity in colonially breeding Blacktailed Gulls (Larus crassirostris)

Kentaro Kazama, Yasuaki Niizuma, Kentaro Q. Sakamoto, Yutaka Watanuki

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls (Larus crassirostris Vieillot, 1818) over 2 years. Only 30%-40% of males attacked a decoy of an egg predator (Large-billed Crow (Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male's, but not female's, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.

Original languageEnglish
Pages (from-to)938-944
Number of pages7
JournalCanadian Journal of Zoology
Volume89
Issue number10
DOIs
Publication statusPublished - 2011 Oct 1
Externally publishedYes

Fingerprint

individual variation
Laridae
nest
breeding
nests
testosterone
Larus crassirostris
egg
laying date
Corvus
crows
birds
clutch size
physiological state
defence
oviposition
incubation
predator
bird
predators

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology, Evolution, Behavior and Systematics

Cite this

Factors affecting individual variation in nestdefense intensity in colonially breeding Blacktailed Gulls (Larus crassirostris). / Kazama, Kentaro; Niizuma, Yasuaki; Sakamoto, Kentaro Q.; Watanuki, Yutaka.

In: Canadian Journal of Zoology, Vol. 89, No. 10, 01.10.2011, p. 938-944.

Research output: Contribution to journalArticle

@article{ac52a27058d34783ba89a5aad3137d90,
title = "Factors affecting individual variation in nestdefense intensity in colonially breeding Blacktailed Gulls (Larus crassirostris)",
abstract = "The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls (Larus crassirostris Vieillot, 1818) over 2 years. Only 30{\%}-40{\%} of males attacked a decoy of an egg predator (Large-billed Crow (Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male's, but not female's, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.",
author = "Kentaro Kazama and Yasuaki Niizuma and Sakamoto, {Kentaro Q.} and Yutaka Watanuki",
year = "2011",
month = "10",
day = "1",
doi = "10.1139/z11-063",
language = "English",
volume = "89",
pages = "938--944",
journal = "Canadian Journal of Zoology",
issn = "0008-4301",
publisher = "National Research Council of Canada",
number = "10",

}

TY - JOUR

T1 - Factors affecting individual variation in nestdefense intensity in colonially breeding Blacktailed Gulls (Larus crassirostris)

AU - Kazama, Kentaro

AU - Niizuma, Yasuaki

AU - Sakamoto, Kentaro Q.

AU - Watanuki, Yutaka

PY - 2011/10/1

Y1 - 2011/10/1

N2 - The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls (Larus crassirostris Vieillot, 1818) over 2 years. Only 30%-40% of males attacked a decoy of an egg predator (Large-billed Crow (Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male's, but not female's, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.

AB - The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls (Larus crassirostris Vieillot, 1818) over 2 years. Only 30%-40% of males attacked a decoy of an egg predator (Large-billed Crow (Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male's, but not female's, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.

UR - http://www.scopus.com/inward/record.url?scp=80055064183&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80055064183&partnerID=8YFLogxK

U2 - 10.1139/z11-063

DO - 10.1139/z11-063

M3 - Article

AN - SCOPUS:80055064183

VL - 89

SP - 938

EP - 944

JO - Canadian Journal of Zoology

JF - Canadian Journal of Zoology

SN - 0008-4301

IS - 10

ER -