Nest Site Location and Nest Success in the Hawksbill Turtle (Eretmochelys imbricata) in Barbados, West Indies
Horrocks JA and Scott MM. 1991. Nest Site Location and Nest Success in the Hawksbill Turtle (Eretmochelys imbricata) in Barbados, West Indies. Marine Ecology Progress Series. 69:1 - 8
Effects of nest location on nest success of hawksbill turtles Eretmochelys imbricata in Barbados were investigated. Hawksbills nested more frequently on west coast than south and east coast beaches, suggesting that they prefer beaches with lower wave energy and steeper beach slopes. Sheltered beaches may be preferred because of the mechanical difficulties and energetic costs of moving onto and off high energy beaches. Hawksbills nested at specific elevations above mean sea level. Elevation was controlled by altering the distance traveled inland on beaches of different slopes. Steeper beaches may therefore be preferred because gravid females and hatchlings may have lower travel costs and lower predation risk. Nest success (number of hatchlings emerging from a nest) was highest from nests closest to mean elevation and declined at higher and lower elevations. This was because emergence success (% eggs laid that emerge as hatchlings) was highest near mean elevation. The high emergence success was due both to a high hatching success (% eggs hatching) and high escape success (% hatchlings escaping from the nest). Emergence success decreased with increasing compaction, due both to an increase in the percentage of dead embryos in nests (late pre-hatching mortality) and a decrease in escape success of hatchlings. Hawksbills preferred to nest amongst vegetation. Vegetated nest sites were less compacted than non-vegetated, and had higher escape success. Hatchling sex ratios were biased towards males on cooler south coast beaches and towards females on warmer west coast beaches. Coastal development may constrain the recovery of hawksbill populations in the Caribbean by forcing females to nest at lower elevations and by increasing compaction through heavy recreational use of beaches and clearance of beach vegetation.
- Type
- Journal Article
- Authors
- Horrocks, J; Scott, M
- Units
- SFCN
- Keywords
- baby, Behavior, breed, Clutch, Hatchlings, Instinct