Sierra Nevada Aquatic Research Laboratory

17 May, 11 AM - 31 Jul, 11 AM

Three factors have been proposed to explain latitudinal and altitudinal variation in avian life history traits: (1) food limitation, (2) adult survival and (3) nest predation. My lab is involved in ongoing studies of four populations of house wrens, northern house wrens (Troglodytes aedon) at low (34? N, 480m) and high (38? N, 2164m) elevations, and low (10? N, 35m ) and high (10? N, 1342m) elevation populations of southern house wrens (Troglodytes musculus) designed to test these hypotheses. At each site, we collect data on clutch size, the duration of incubation and nestling periods, female time investment in incubation and its impact on nest vs. ambient temperature, nestling growth rate, male versus female feeding rates, parental response to predator presentations and nesting success. During the 2004 and 2005 breeding seasons, we are conducting experiments designed to directly test the hypotheses listed above. At SNARL, we hope to continue monitoring nests using behavioral observations and temperature loggers. In addition, we propose to (1) supplementally feed chicks in 10 nests to test the food limitation hypothesis and (2) conduct observations of parental response to 15 min. presentation of artificial snake presentations at nest boxes. Each of these experiments follows protocols used at other sites. The latter experiment is designed to test the nest predation hypothesis, following up on our observation that patterns of nest defense parallel local snake predation pressure. Potential impact: We will continue to maintain the house wren boxes at SNARL that we have used in previous years. That is, any mice will be removed and boxes will be cleaned with bleach solution at the start/end of each field season and wires holding boxes to trees will be loosened and moved at this time. Our previous work at this and other sites suggests that none of our behavioral observations, including artificial snake presentations, have any long term consequence on behavior or reproductive success. This year, we plan to supplementally feed house wren chicks with meal worms. Our intent is to place a feeding dish on top of the nest box and to fill it with a standardized number of mealworms each morning. We will observe these boxes to determine if parents do, in fact, locate this new resource (as they have in other studies), and monitor feeding behavior. Dishes will be removed, cleaned and replaced daily. This may have the impact of shortening development time of chicks such that they fledge earlier than chicks who do not receive food supplementation.

Visit #6729 @Sierra Nevada Aquatic Research Laboratory

Approved

Under Project # 5053 | Research

Understanding Variation in Life History Traits: Tests with House Wrens

faculty - Pomona College

Reservation Members(s)

Rachel Levin May 17 - Jul 31, 2005 (76 days)
Rachel Levin May 17 - Jul 31, 2005 (76 days)
Group of 2 Undergraduate Student May 17 - Jul 31, 2005 (76 days)

Reserve Resources(s) | Create Invoice

Dorm 4 May 17 - Jul 31, 2005
Office 4 May 17 - Jul 31, 2005
Q1 4 May 17 - Jul 31, 2005
Q2 4 May 17 - Jul 31, 2005
Q8 4 May 17 - Jul 31, 2005