Sorry for the lack of updates the past few days — there’s been plenty going on, some of it behind the scenes (more about that shortly). One friend commented today, “You guys must be running around like your hair’s on fire.” That pretty much sums it up.
In Wisconsin, SNOWstorm collaborator Gene Jacobs has been trying to tag two more owls, but has been up against some bad luck the past couple of days, including flocks of crows that harassed one owl to the extent that it wouldn’t come to the lure. He’ll be out again this week, though, working in eastern Wisconsin where there are a lot of snowies.
In Massachusetts, SNOWstorm collaborator and veteran snowy owl researcher Norman Smith was on CBS News last week talking owls.
The news on Assateague and Buena Vista is that is there is no news. Looking at cell tower location maps, we think there’s a good chance that both birds have moved into areas with limited cell coverage.
That doesn’t effect the GPS data – the units will continue to record locations around the clock. But the transmitters are programmed to only dial in once a day through the cellular network to transmit their stored data. This is an energy-saving measure. Receiving signals from the orbiting GPS satellites doesn’t take a lot of juice, but (as you know if your cell phone has ever drained its battery searching for a signal) connecting to the cell network takes a lot of energy.
If the owl is in a dead zone when the transmitter tries to call in, the unit shuts down and tries again at the same time the next day — and the next, and the next, until the owl moves back into range and can connect. Fortunately, the units continuously log GPS coordinates — so while we may have to wait a bit to get it, we’ll have a pile of fresh data once the transmitters do check in. Unfortunately, patience has never been one of my virtues.
Because these CTT transmitters have never been used on owls, and were designed for diurnal birds like eagles that are most active when solar recharging is at its peak, we’re experimenting with how to maximize data collection at night without draining the small battery.
So the next batch of transmitters we’re putting out are set to a new duty cycle. At night, the transmitter will record a GPS position every 15 minutes instead of the current half-hour, giving us an even better sense of the nocturnal movements of the birds. (Compare that to a satellite transmitter, which typically records only one or two locations every 24 hours.)
Assateague and Buena Vista’s units are programmed to “phone in” in mid-afternoon — great for day-flying eagles, but the owls are usually sitting on the ground asleep at that time, making it even harder for the transmitter to find good cell reception. So the new transmitters will phone in after dark, when the owls are up and flying – and to do so only every third day, as a means of saving battery power in prolonged periods of clouds and precipitation.
One great feature of these CTT transmitters is that they can be reprogrammed on the fly, so to speak — so when Buena Vista and Assateague’s units do finally call home, we will upload the fresh duty cycle while downloading their backlogged data.
One thing we’re not worried about is losing data. These transmitters can store up to 100,000 GPS locations – which, at every 30 minutes, is 5.75 years’ worth of data before they reach their capacity.
But it’s that patience thing, again. Like all of you, I’m anxious to see where our birds have been lately.