Methodological problems in studies of avian nest defence

During nest defence, yellow warblers (Dendroica petechia) give "seet" and "chip" calls. Seet calls are given preferentially toward brood parasitic brown-headed cowbirds (Molothrus ater) during the yellow warblers' egg-laying period, whereas chip calls are given toward mammalian and avian nest predators throughout the nesting period. In this study, we investigated two possible functions of seet and chip calls during nest defence by playing alarm calls to nesting yellow warblers. We tested whether nest owners give seet and chip calls during defence to alert their offspring and their mates about nest threats and, in the latter case, whether the alarm calls differ in function depending on nesting stage. In response to playbacks, nestlings remained inactive for a significantly longer period when chip calls were played than when seet calls were played. Female yellow warblers returned to their nesting areas more quickly when seet calls were played than when chip calls were played, but pairs were equally likely to return to the nesting area in response to both call types. These findings suggests that both seet and chip calls alert mates but that only chip calls function to alert nestlings of potential danger.

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Evolutionary significance of antiparasite, antipredator and learning phenotypes of avian nest defence

Scientific Reports ◽

10.1038/s41598-018-28275-3 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 8

Author(s):

Daniela Campobello ◽

Spencer G. Sealy

Keyword(s):

Nest Defence ◽

Evolutionary Significance ◽

Avian Nest

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Nest Defence By Yellow Warblers: Recognition of a Brood Parasite and an Avian Nest Predator

Behaviour ◽

10.1163/156853996x00143 ◽

1996 ◽

Vol 133 (3-4) ◽

pp. 263-282 ◽

Cited By ~ 56

Author(s):

Sharon A. Gill ◽

Spencer G. Sealy

Keyword(s):

Brood Parasitism ◽

Nest Defence ◽

Brood Parasite ◽

Yellow Warbler ◽

Nest Protection ◽

Yellow Warblers ◽

Avian Nest ◽

Defensive Behaviours ◽

And Control ◽

Nest Predator

AbstractYellow warblers (Dendroica petechia) were exposed to taxidermic mounts of a brood parasite (brown-headed cowbird, Molothrus ater), avian nest predator (common grackle, Quiscalus quiscula) and control (fox sparrow, Passerella iliaca) during their laying and nestling stages to determine whether nest owners distinguish between the threats of brood parasitism and predation. Yellow warblers responded more intensely to the cowbird at the laying stage, performing two unique behaviours (seet calling and nest-protection behaviour) in response to this threat. By contrast, yellow warbler responses to the grackle were greater at the nestling stage, consisting largely of alarm calls (chip, metallic chip and warble calls). The sparrow model infrequently elicited aggressive behaviour from nest owners at either stage. These responses support the hypothesis that yellow warblers discriminate between threats of brood parasitism and nest predation. Yellow warblers may perform specific behaviours to cowbirds because defensive behaviours used against predators may be incompatible with cowbird deterrence. Female nest owners responded more frequently than males at the laying stage, and more intensely than males at both nesting stages. The distance that females and males approached the models and several aggressive behaviours were positively correlated. The greater responsiveness of females may be because they dominate their mates and because females are more experienced with intruders near the nest.

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Does the intrusion of an avian nest predator elicit a change in the behaviour of a canopy-nesting passerine?

Behaviour ◽

10.1163/1568539x-bja10078 ◽

2021 ◽

pp. 1-26

Author(s):

Alexander R. Sharp ◽

Kamal Islam

Keyword(s):

Nest Defence ◽

Cyanocitta Cristata ◽

Potential Predator ◽

Reduce Activity ◽

Provisioning Rate ◽

Avian Nest ◽

Cerulean Warblers ◽

Stage 1 ◽

Nest Predator ◽

Nest Predators

Abstract Many studies have shown that nest predators affect their prey indirectly by inducing changes in the behaviour of the prey. Studies suggest that the type and degree of nest defence strategies depends heavily on species, along with nest type and location. One such strategy, nest vigilance, allows individuals to collect information and make informed decisions based on their surroundings. In this study, we simulated the intrusion of a common avian nest predator (blue jay, Cyanocitta cristata) into the territory of nesting cerulean warblers (Setophaga cerulea) and evaluated eight different behavioural variables to determine their response to the nest predator. Female cerulean warblers were more vigilant on their nest when exposed to a potential predator compared to a nest with lower threat of predation. Females exposed to a nest predator increased incubation bout by 109% and brooding bout by 60%. Our data also suggest that male cerulean warblers reduce their provisioning rate during the early nestling stage (−1 feeding/hour) and late nestling stage (−3 feedings/hour), although more data are needed. Modification of incubation bout length and nestling provisioning rate are common strategies employed by songbirds to reduce activity around the nest, by decreasing detection opportunities of visually-oriented nest predators. Currently, the only understanding we have on how cerulean warblers respond to a nest predator is based on observational data. The results of this study provide the first evidence that cerulean warblers are able to identify species that pose a threat to the safety of their nest, and that they modify their behaviour to reduce nest detection by predators. The results of this study provide a better understanding of a relatively unknown aspect of the breeding behaviour of this species. This study is also first to describe how an open-cup, canopy-nesting species responds to an increase in nest predation threat.

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Avian Nest Defence: Theoretical Models and Evidence

Behaviour ◽

10.1163/156853989x00646 ◽

1989 ◽

Vol 111 (1-4) ◽

pp. 161-195 ◽

Cited By ~ 83

Author(s):

Tomas Redondo

Keyword(s):

Theoretical Models ◽

Nest Defence ◽

Avian Nest

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Theoretical and Methodological Problems of a 10-Year Follow-Up Program Evaluation Study

European Journal of Psychological Assessment ◽

10.1027//1015-5759.18.3.229 ◽

2002 ◽

Vol 18 (3) ◽

pp. 229-241 ◽

Cited By ~ 6

Author(s):

Kurt A. Heller ◽

Ralph Reimann

Keyword(s):

Program Evaluation ◽

Evaluation Studies ◽

Evaluation Study ◽

Control Groups ◽

Cross Sectional ◽

Long Term Study ◽

Partial Inclusion ◽

Methodological Problems

Summary In this paper, conceptual and methodological problems of school program evaluation are discussed. The data were collected in conjunction with a 10 year cross-sectional/longitudinal investigation with partial inclusion of control groups. The experiences and conclusions resulting from this long-term study are revealing not only from the vantage point of the scientific evaluation of new scholastic models, but are also valuable for program evaluation studies in general, particularly in the field of gifted education.

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