Nazca Booby Reproductive Data

The following link will upload to the user an MS Excel file with reproductive data from Nazca boobies (Sula granti) at Punta Cevallos, Isla Espanola, Galapagos, Ecuador. The data were collected by Dave Anderson's research group at Wake Forest University; please contact Dave if you intend to use these data

The data were collected from the 1992-93 breeding season to the 2006-07 breeding season, inclusive, from our "Study Area", a subarea of our research site in which we monitor all nests every year. We do not conduct experimental manipulations in the "Study Area". These data are thus appropriate for inter-annual comparisons of productivity and population-level performance. We are proofing the 2007-08 data and will be adding those shortly.

The variables in the file are:

Nest: marked nest number
Re-nest: 0 if not a re-nest, 1 if a re-nest
Year: which breeding season
Eggslaid: clutch size
Estlayda: estimated lay date, sometimes known with certainty and sometimes estimated as hatch day-43
Htchno: number of hatched eggs
Hatchday: hatching date
Chick 1%: date that the chick reached the developmental stage at which only 1% of its down remained attached
Dethday: date of chick death
Numfledg: number of fledglings produced

A note on dates. We use a convention that is meant to simplify time-based analyses for a species that begins breeding in one year (in September) and finishes breeding in the next year (June). Dates can range from 1 to 730, and represent a day within a two-year period. For example, an egg laid on the last day of 1997 would have 365 in the Estlayda variable. If that egg hatched 43 days later, the Hatchday variable would have 408 ( = 365 + 43 ). Our date is essentially a two-year Julian calendar.

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