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Redmond, Roland L. The Behavioral Ecology of Long-Billed Curlews (Numenius Americanus) Breeding in Western Idaho. Montana: University of Montana, 1984
This detailed dissertation is framed within three points of view: “1) that individual animals exploit environmental resources by behavioral means, 2) an animal’s behavior is adapted to a certain set or sets of ecological conditions, and 3) an individual’s performance of any given behavior will depend on immediate ecological conditions as well as on the behavior of conspecifics [members of the same species] (or others) simultaneously interacting together.” – p. 1 This idea that a species will adapt its behavior to its environment is interesting and allows us to understand why certain sites where prey is numerous can contain more breeding pairs than a site where prey is scarce. The additional factor of how behavior is influenced by the neighboring curlews and other bird/non-predatory animal species is something I hadn’t really thought about.
The dissertation is focused on four topics:
1. Social organization
2. Population ecology
3. Egg size and laying date
4. Natal philopatry [returning to area of birth] and breeding area fidelity
From the Abstract of Chapter 2:
“Breeding behavior and ecology of long-billed curlews (Numenius americanus) were studied by observing color-marked and radio-marked individuals for three years (1977-1979) in western Idaho. The mating system was a resource-defense form of monogamy. Males selected and defended large (~14 ha) territories that were normally used by both members of a pair for feeding and nesting. Territorial males without mates advertised their status to available females by performing conspicuous display flights around the perimeter of their territory. Observations suggest that both members of many pairs arrived on their previous year’s territory at nearly the same time, or perhaps together. Courtship behaviors were much reduced among these pairs, and consequently they were the first birds to nest each year.” – p. 4 To me this means I have a longer period of time to see courtship behaviors as some pair early and some late. I had not thought about how pairing early would make the defense of territory easier.
“The Undulating Flight Display
Territorial males without mates advertised their status by performing undulating flight displays (UFD’s).” This is an arcing flight with a steep upward with “rapid, shallow wingbeats” and a gradual descent while giving out a “low whistle call” – p 12
I’m including his drawing because it really helps visualize this display. Normally the flight of Long billed curlews is horizontal excepting landing and taking off.
There’s so much detail in this dissertation that I’m not going to include anything else. If you are interested in Long billed curlews I recommend finding a copy of this dissertation through Interlibrary Loan or at your nearby academic library which may subscribe to the “ProQuest Dissertations & Theses” database. Sorry not all academic or university library will subscribe to the database which is why I’m also suggesting interlibrary loan which most public libraries provide. You may end up with microfilm.