Nest Monitoring

During the nesting season (normally from April to January), STCB staff and trained volunteers patrol the beaches most used by turtles, recording signs of nesting and hatching, as well as monitoring the safety status of nests.

Nesting season on Bonaire
On Bonaire, sea turtles nest between May and December. Bonaire’s most important nesting site is Klein Bonaire. Every season, approximately 50-70 sea turtle nests are laid in this area alone. Sea Turtle Conservation Bonaire (STCB) staff and trained volunteers patrol the beach of Klein Bonaire three mornings per week to look for new activities, such as crawls, attempts and nests. When an activity is found, we stop our patrol to take a closer look at the activity. We start by taking photos of the activity and calculating the exact location with our GPS. We then look for clues which tell us whether a turtle dug a nest and deposited eggs, or whether she returned to the ocean without laying a nest. If we do suspect the activity to be a new nest, we try to locate the eggs so that the nest can be protected during the two months of incubation. Locating a new nest may take up to 30 minutes.

From July onwards, we also check the beach for hatched nests. When we find a nest that has hatched, we excavate the nest to collect data on species and hatching success. We count empty egg shells and dead eggs, take measurements and release hatchlings that were left in the nest (e.g. because they were stuck behind roots). Normally, sea turtle hatchlings will leave their nest at night or very early in the morning as this is the safest time for them to start their journey. By the time that we excavate a nest, most hatchlings will have already made their way to the sea.

Joining a nest monitoring patrol
If you would like to learn more about sea turtles and the work that we do, you can join a nest monitoring patrol on Klein Bonaire. We go on Mondays, Wednesdays and Fridays. We meet at Plaza Marina at 7:30am, from where we will go to Klein Bonaire in our boat. On Klein, we patrol the 2km long beach to look for new activities. You will join our staff and trained volunteers during their patrol. The patrol will take about 3 to 5 hours depending on the number of activities we find – sea turtles are pretty unpredictable, we cannot guarantee finding any activities. Please note that walking is difficult on the wet rocks and in the tide, so suitable footwear is important for your comfort and safety (e.g. sandals, diving boots). We also recommend you bring water and sun block.

To support our work, we ask for a $40 donation for adults and $20 for children under 12 (and residents). This money is used to pay for gasoline for our boat and to make nest barriers for nests that need additional protection.

Please send us an e-mail to make a reservation.


STCB Nest Counter

Nesting season 2022 started in May.

Number of nests on Bonaire

0

Number of nests on Klein Bonaire

0

Total number of nests

0


Nesting and Hatching on Bonaire

  • nesting-season

    Bonaire’s beaches receive an annual average of 75 nests. How do we know that it’s important to protect these nests in the interests of sea turtle survival? We know because detailed counts reveal that large nesting colonies are rare. For example, only 0.4% of all known species-specific nesting sites in the Wider Caribbean Region receive more than 1000 hawksbill crawls per year. On the 1,311 known nesting beaches in the region, roughly half support fewer than 25 nest crawls per year. These counts provide an important perspective. It turns out that protection of the many small nesting colonies is critical if we are to maintain hatchling production and genetic diversity.

  • nest-inspection

    The research yields important information over time about population status. By comparing nesting data from year to year, we gradually see trends emerge. Because annual variation in nesting activity is normal in marine turtles, only data collected long-term (more than 10 years) will be truly indicative of how healthy these nesting turtle populations are.

    In an effort to understand how nest temperature is affecting the ratio of male to female hatchlings on Klein Bonaire, Playa Chikitu and on beaches in the south of Bonaire, STCB is participating in a pilot study initiated by IAC and is using temperature dataloggers, deployed at nest depth, to monitor sand temperature in 2021-2023.

  • Trapped-hatchling

    This interesting study is based on our knowledge that for sea turtles, sex is not determined at fertilization. Instead, temperature plays an important role: eggs in warmer nests tend to develop into females, and cooler nests produce more males.

    This study may give us insights not only into the relative numbers of males and females produced on Bonaire, but also into the long-term effects of climate change.

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