Hydrophone / Nest Videos

For the past few years some nest parents and volunteers used stethoscopes to listen for noise made by embryos/hatchlings as they hatch and then make their way to the surface of the sand. During this time, it is thought hatchlings are getting organized, likely communicating with each other through subtle vocalizations and body contact to improve synchronization for emergence. There is also time for the closing and straightening of the plastron (bottom shell). From pipping (when eggshell is first slit) to emergence takes on average about 5 days.

In 2017 N.E.S.T. invested in multiple hydrophones, highly sensitive waterproof microphones. The microphone is buried in the sand near the nest and transmits sound through a long cable to ear phones, a speaker and or a recorder. By using the microphone more sounds were heard and everyone at the nest could listen. Pipping (hatchlings breaking their shell) and early movement sound like someone tapping and or “moving furniture.” The falling sand of a hatchling making its way to the surface sounds like a “waterfall” or even a “roaring waterfall” when hatching is imminent.

The microphone is the black disc in the lower right hand corner.  The receiver is in the upper right hand corner and speaker in upper left hand corner.

The Tale of 2017 Nest 16

Nest 16 was a late nest. Nest parent, Susan Silbernagel, was due to have her team start sitting the nest on day 65.  On day 63, during the first spot check with a microphone Susan’s team heard “furniture moving” sounds and the next day rat tat tat sounds.  They were encouraged that despite the lateness of the nest, the embryos were alive and they would get a hatch. On day 65, however, no sounds were heard and there was only silence every day after that. What had happened?

On day 90 the nest was excavated.  Susan’s team found cracked eggs (pipped) with fully developed embryos but not a single embryo had found its way out of the shell.  The sounds heard (furniture moving and tapping) may have been the sound of the embryos pipping. The embryos, however, were unable to make it out.  A possible clue is that the average nest temperature was about 79˚F, a good 4 degrees below the optimum range that produces strong, vigorous hatchlings. In addition, the average temperature from day 54 to day 63 was a cold 74.4˚F. So presumably, the embryos were too weak to emerge.

Hydrophone Recordings:

Note: During the quieter times you can hear ambient noise of voices, wave action and sand blowing.

This clip is of sounds including gentle tapping noises and what we call “furniture moving” noises possibly embryos/hatchlings piping (breaking their shells) and getting organized 3 days before the hatch of 2017 nest 3

This short clip is of early sounds of hatchlings moving around at 2017 nest 2

This is a recording of 2017 nest 14 furniture moving sounds and early water fall.

This recording is of 2017 nest 1 shortly before a hatch.  The intense waterfalls sounds come in waves as the hatchlings are making it to the surface.

Videos

The video here is of the excavation of nest 14. Nests are excavated a few days after hatching to assess the percent of the eggs that hatched and the health of the nest.