Summary: Actuarial and reproductive senescence in a long-lived seabird: preliminary
D.J. Andersona,*, V. Apaniusb
Department of Biology, Wake Forest University, Winston-Salem, NC 27109 7325, USA
Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
The evolutionary theory of aging predicts that pelagic seabirds, which have low extrinsic mortality, should show exceptional longevity.
These taxa appear to show the lowest rates of actuarial senescence among birds yet display declining reproductive performance at advanced
ages. We have studied survival and reproduction of Nazca boobies (Sula granti) in the remote Gala´pagos Islands since 1984. We found a
slight but detectable increase in mortality rate in the oldest ($19 yrs) cohort, indicating minimal actuarial senescence. The probability of
successful reproduction (eggs or fledglings) declined from mid-life to the age of the oldest cohort. We are currently investigating the causal
relationship between physical (foraging) performance, components of reproductive success, and longevity at our pristine study site.
q 2003 Elsevier Science Inc. All rights reserved.
Keywords: Reproduction; Actuarial senescence; Seabird; Nazca booby; Sula granti
Birds and bats live longer for their body size than do
non-flying mammals, probably because flight protects them
from some sources of extrinsic mortality (Calder, 1983;