Useful tips for monitoring an emerging nest
On Sunshine Coast beaches emerging hatchlings are usually seen from mid January until late March, or even into April/May depending on the season. They usually exit their nests in the cool of the evening - generally before 10pm. Incubation periods vary according to weather conditions and local sand temperatures so you may not get to see the hatchlings emerge on your shift.
Because the shape and compaction of the sand in the chamber is critical to the survival of eggs and emerging hatchlings, do not dig into the chamber at any time over the incubation period. Disturbance of the chamber can result in disruption of the gas exchange process within the nest, compaction of the chamber and alteration of the shape of the chamber wall, all of which can decrease the survival rate of hatchlings at emergence time.
In the egg chamber, about half a metre under the sand, the hatchlings break out of their eggs within a few hours of one another and it will take around 24 hours for them to straighten out and leave the eggshell. They then wait and start climbing to the surface as a group and this may take up to 2 days. The group then usually emerges onto the surface in a rush and it may only take around 10 minutes for all to emerge. Some hatchlings may take longer so during this critical time do no disturb the chamber as you may trap hatchlings. Please remember the following hints when monitoring a nest for emergence:
- We cannot exclude members of the public from our beaches during hatchling emergence so invite them to wait quietly with you but reinforce that they may not see anything, and that it is important that they do not use torches or cameras with flashes during the hatchling emergence and passage to the beach;
- Hatchlings can actually emerge through the protective mesh so do not remove the protective mesh as not all hatchlings may emerge with the main group;
- On beaches where there is intrusive lighting from parks, streets and housing you may need to use a gutter guard barrier around the rear of the nest to funnel the hatchlings down the beach away from inappropriate light sources. The last monitoring group for the night should remove this from around the nest.
- Always keep clear of the nest as you may inadvertently push sand into the nest, restricting the progress of hatchlings below;
- Allow the hatchlings to emerge naturally and exit the beach without interference. Hatchlings are imprinted to the dip and strength of the earth�s magnetic field. Handling the hatchlings interferes with this process, which may be particularly critical for female hatchlings that will use that imprint to return to the same area for nesting in 30-50 years time.;
- AVOID USING TORCHES OR CAMERAS WITH FLASHES as they easily disorientate hatchlings, hindering their race to the ocean. If hatchlings are following lights everywhere they are more likely to be trodden on and they are wasting precious energy that is needed for their swim away from coastal waters;
- If other residents or visitors are on the beach please explain why the use of torches and cameras and handling of hatchlings is prohibited;
- If visitors ignore requests to form a clear path to allow hatchlings to progress unhindered or attempt to handle hatchlings you may have to install barrier mesh to prevent them from walking on or handling hatchlings;
- Be aware that hatchlings may still turn around once on the beach so often a low sand wall from either side to the nest to the water may contain them as well as being useful for forming a designated vantage point for visitors;
- Some members should monitor the waters edge to ensure that hatchlings are not attracted back from the water by external lighting or torches because the longer they stay inshore the more prone they will be to being eaten by predators;
- You may (attempt to) count the hatchlings if you wish but this is not used as part of the official data collection so is not absolutely critical. The chamber will be checked and data collected by accredited volunteers around 2 to 5 days after the hatchlings emerge;
If hatchlings emerge on your shift:
- Make a note of the date and time the hatchlings emerged;
- Contact the members rostered on after you to let them know this has occurred because they will not be required unless another nest on the same beach is due to emerge around the same date;
- Cross the tracks (drawing distinct lines in the sand across the hatchling tracks); and
- Contact the Coordinator within 12 hours to provide details of nest location, emergence time, date etc.