Meeting Abstract

P3.128  Tuesday, Jan. 6  Don’t count your chicks before they hatch: an experimental manipulation of incubation effort in Leach’s storm-petrel (Oceanodroma leucorhoa) HARN, L.J.**; HAUSSMANN, M.F.; MAUCK, R.A.; Kenyon College, Gambier, OH; Bucknell Univ., Lewisburg, PA; Kenyon College, Gambier, OH harnl@kenyon.edu

Parents must allocate available energy between the competing demands of self-maintenance and offspring care. Long-lived species such as Leach’s storm-petrel (Oceanodroma leucorhoa) may invest preferentially in self-maintenance because any one reproductive event comprises only a small proportion of lifetime reproductive success. Recently, our lab has shown that sex of storm-petrel individuals may also influence allocation of resources, since females invest energy into egg production while males may expend more energy during incubation and chick rearing. During the early incubation period we increased the energetic cost of flight by trimming the outermost 1.5 cm of the primary remiges for one, both, or neither member of breeding pairs. We used length of the incubation period and egg neglect as measures of parental effort and the re-growth rate of an induced outer right rectrix as an index of energy allocated to self-maintenance. Mean feather growth rates for breeding pairs were positively correlated with length of the incubation period (P=0.009). However, incubation length, individual feather growth rate, and mean feather growth rate were not affected by Julian lay date (P= 0.7) or experimental group (P > 0.5). Preliminary analyses of known-sex individuals indicate that feather growth rate did not differ by sex (P=0.18). Feather growth rate for sham treatment individuals (0.86 +/- 0.07 SE mm/d) did not differ significantly (P=0.15) from that of trim treatment individuals (1.01 +/- 0.07 SE mm/d). Analysis of iButton temperature and PIT technology data will allow us to assess the relationship between incubation period, individual attendance patterns, egg neglect, and feather growth.