Ardea

Reproductive performance, mate fidelity and nest cavity fidelity in Red-billed Tropicbirds Phaethon aethereus mesonauta on St. Eustatius, Caribbean Netherlands

Mate choice and nest cavity selection are directly linked to reproductive performance in seabirds, and disruption of these can result in breeding failure. The Redbilled Tropicbird Phaethon aethereus mesonauta breeds on inaccessible and remote islands, nesting primarily in natural rock cavities. I examined the relationship between reproductive performance and mate and nest cavity fidelity on St. Eustatius from 2012 to 2016, corresponding to four successive breeding seasons. The majority of nest failures occurred during the incubation stage. Pairs that failed in their first breeding attempt and laid a replacement clutch were more likely to be faithful to their mate and nest cavity within and between seasons than pairs that bred successfully. Only two replacement clutches (3.8%) were laid after the loss of a chick in the first breeding attempt, whereas the remaining 50 replacement clutches (96.2%) were laid after the loss of an egg. The stage at which pairs split had no influence on mate or nest cavity retention the following season. There were no significant differences in the weight or morphological measurements of chicks from pairs that retained their nest mate and/or cavity and those that switched. The results of this study suggest that switching nest mate or nest cavity does not necessarily improve subsequent breeding success among Red-billed Tropicbirds on St. Eustatius.

Key words: mate fidelity, nest cavity fidelity, Phaethon aethereus mesonauta, reproductive performance

 

Contact: Hannah Madden (Hannah.Madden@cnsi.nl)

Date
2019
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
St. Eustatius
Author
Private Document

Breeding success of Red-billed Tropicbirds Phaethon aethereus on the Caribbean island of Saba

In 2011 and 2012 the breeding success of Red-billed Tropicbirds Phaethon aethereus mesonauta was monitored on Saba, a 13-km2 island in the Caribbean Netherlands. The two colonies on the south and south-west side of the island both contain approximately 100–300 nests; breeding success was zero at these sites, due to predation of newly hatched chicks by Feral House Cats. In the single large colony of Old Booby Hill (estimated to contain approximately 1000 nests) on the east side of the island, rates of predation were lower, resulting in a breeding success (survival from laying until fledging, as far as observed) of 65%. Calculations of daily survival of eggs and chicks following Mayfield, resulted in a nesting success of 48% per pair. I conservatively estimated the size of the Saba breeding population to be at least 1300–1500 pairs, which is larger than the previous estimate of 750–1000 pairs. Potentially, the number of breeding pairs may be as high as 1850 pairs. 

Date
2016
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Saba
Author