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The Montana Cooperative Wildlife Research Unit

The University of Montana

Juan Carlos Oteyza - Ph.D. Candidate

Advisor- Tom Martin

Natural Science Building - Room 311
Phone: 406-243-4396

Juan in Borneo
Juan in Borneo

2011 (exp) M.S., Wildlife Biology, The University of Montana
2004 B.A., Environmental Science (minor in Geography), Boston University

I am broadly interested in ecology, animal behavior and evolutionary biology. Since 2004 I have worked in several ornithological field research projects in different tropical habitats. I first joined Dr. Thomas E. Martin’s long term study on the geographic variation in avian life history traits and parental care behaviors in 2007. Since then I have worked in his Venezuela field site, supervised the laboratory in Montana and the Borneo (Malaysia) field site. I started my Master's project in 2010 in Borneo and will continue to collect data in 2011.


 Understanding life history strategies that influence offspring size.


Offspring size is a critical trait because it has important consequences for survival and reproductive success. Traditionally one of the main factors thought to influence size of dependent offspring (i.e., those that depend on parents for care) is parental food delivery rates. The ability of parents to deliver food is thought to be limited by food abundance. Therefore, number of adults contributing to care may influence food delivery rates. Number of adults contributing to care is particularly variable in cooperatively breeding birds, where parents may be aided in parental duties by helpers. However, many studies have failed to detect an increase in offspring size with an increase in number of helpers. To understand this paradox where number of helpers seem to have no effect on offspring size, I am studying traditional ideas involving feeding rates and alternative hypotheses related to female condition and incubation temperature.

 I am studying the breeding behavior of two cooperatively breeding passerine birds in the family Timaliidae: Chestnut-crested Yuhina (Yuhina everetti - see picture above) and Mountain Wren-babbler (Napothera crassa). These two species represent opposing ends of the slow-fast life history gradient.  Their differences in developmental speed, egg size, and parental care provide a basis for examining how offspring size is related to life history strategies. Number of adults helping the main pair varies from one to eight individuals for these species. The first season of field work took place in 2010 at Kinabalu National Park in Malaysian Borneo.  A second season of work will take place in 2011.

 Progress and Status:

The 2010 field season in Malaysia was very fruitful with a total of 112 nests found for both species of interest. A total of 143 adult birds were uniquely color banded to be able to identify individuals at their nests. 334 egg masses and 377 nestling measurement were recorded, hundreds of hours of videos data, as well as egg temperature data (13 nests) and incubation attentiveness data (47 nests), all of which I am currently analyzing. 

Natural Sciences Room 205

Missoula, MT 59812