We currently have about a dozen sensors installed in nests, but only three of them are connected to communications devices. For the first month after a clutch of eggs is laid, there is little or no activity in the nest. Since this is the first testing of our devices in the field, we want to fix any bugs in the first devices before sending out lots more.
The first communicators were installed around the end of June, just in time to be tested by some very extreme conditions during Hurricane Arthur. We didn't know what to expect. Would the cement anchors on the PVC pipes that house the communicators be secure enough? Would water find a way into our hermetically sealed enclosures? Would the nests get washed away? We changed the parameters on the units so that they phoned in every two hours instead of once a day. We figured if the units failed, we'd get information right up until two hours before they failed. As we watched the hurricane forecasts, the storm track was pointing directly to where our first devices were installed.
The units made it through the Category 2 hurricane without any problems. So, now we know that they can handle severe weather. We also learned something very important from the storm. We had been worrying that environmental noises and disturbances might make it hard to tell the difference between those disturbances and hatching eggs. What we found from the data during the hurricane is that it is very quiet a foot or two feet below the beach. The noise level from crashing waves, blowing sand, and torrential rain was barely noticeable in our data. On our logarithmic scale, that means that the noise level during the storm is no more than about 40 percent above normal. Since our scale has about a 1:1,000,000 range, 40 percent is not significant. The noise level we are encountering in the nests is comparable to the noise level on the table in my empty kitchen when I was testing the sensors overnight.
So what does this mean about the motion we will record as the embryos start moving and later when the eggs start hatching? This is the big unknown. We'll find out soon.