The nocturnal behaviors of yellow-breasted chats

Alessi, Mark G.

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https://hdl.handle.net/2142/16144 Copy

Description

Title

The nocturnal behaviors of yellow-breasted chats

Author(s)

Alessi, Mark G.

Issue Date

2010-05-19T18:38:36Z

Director of Research (if dissertation) or Advisor (if thesis)

Ward, Michael P.

Department of Study

Natural Resources and Environmental Sciences

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• nocturnal movements
• conspecific attraction
• yellow-breasted chats
• habitat selection

Abstract

Yellow-breasted Chats (Icteria virens) are a Neotropical migratory bird species that breeds in shrubland habitat in Illinois. Chats are a diurnally active species but males are known to sing often at night. This behavior suggests that chats may engage in other behaviors related to breeding at night. I investigated whether chats engage in significant movements at night, and if so, why. I used an automated radio telemetry system to quantify the nocturnal movements of male and female chats. I found that males and females moved at night, and that they moved significantly more often when the female of a given pair was fertile. Both males and females moved most often on nights when the moon was least illuminated, but there was no indication that birds engaged in more movements at a certain time of night or during a specific stage of the breeding season. These data, combined with data from other studies of extra-pair copulations and extra-territorial movements of chats, suggest that birds might engage in these movements to assess potential mates and/or copulate with an extra-pair mate. Foraying nocturnally on dark nights by females may allow them to stay undetected by their mates. Night song may also serve as a cue of habitat quality to migrants during both the spring migration and during the breeding season. Like most other passerines, chats migrate at night and likely select a place to land, either their final destination or a stopover site, while it is still dark or shortly after sunrise. I attempted to attract migrating chats to a predetermined site that lacked appropriate habitat by playing chat song at night. If nocturnal song was used by chats when selecting breeding or stopover sites, then I expected to capture chats on nights when I played chat songs. Significantly more individuals (eight males, seven females) were captured on mornings following treatments (playbacks conducted) relative to control nights when no songs were broadcast (2.5 vs. 0.0 birds/morning, respectively). This research has documented that nocturnal behaviors are common in chats and that these behaviors may be important in the selection of mates and habitats. Little attention has been paid to what diurnally active birds do at night; however, this study highlights the potential importance of nighttime activity.

Graduation Semester

2010-5

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http://hdl.handle.net/2142/16144

Copyright and License Information

Copyright 2010 Mark G. Alessi

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