If you study plants, studying how they change can be pretty easy (from a logistical stand point). Sessile plants and animals can be found where you left them. Awesome. It saves guess work or the laborious task of tracking individuals to even start and continue studying your target species in any longitudinal research. However, for many of us, studying living creatures means accommodating the fact that they move around. Sometimes across fields, across lakes or even across continents.
I study migrating birds, but not just any migrating birds; long-distance arctic-breeding shorebirds. These species fly some of the longest recorded migrations known on the planet. They never stay in one place for very long so we have to work hard and fast when they are around and prepare to monitor movement once they decide to leave.
Historically, the larger the animal, the easier it was track. Not only are larger animals more conspicuous but larger animals can carry larger markers like flags on their legs or brightly coloured collars around their necks. They can also carry around heavier devices which are ideal for satellite tracking requiring larger heavy batteries and larger antenna to transmit signals out into space.
Unfortunately for many of us, we could only dream of tracking our much smaller highly mobile animals across large distances. And we are still dreaming. But until some wonderful engineer makes our dreams come true and designs a satellite tracker weighing less than half a gram, we have devised (meaning lots of people, not including me) ways of tracking animals using other kinds of information-transmission other than satellite signaling.
I track and monitor migratory movements of small shorebirds weighing between 50 and 300 grams using radio telemetry. Telemetry has been around for a long time but was only really used locally where a handheld receiver could detect signals on foot for a kilometer or so depending on terrain. But collaborative efforts with academics, along with provincial and federal governments, we now have the MOTUS wildlife tracking system (http://motus-wts.org/) .
Small radio tags emit pulses in unique patterns on the same radio frequency that can be detected by towers set up all over Eastern Canada and the North-East coast of the US. Density of towers in the Southern Ontario region basically cover the entire area so we can monitor “microscale” movements of birds through the Great Lakes region.
Battery life ranges in the tags from 60-180 days and then will fall off when the bird molts . Tags are only glued to the body feathers which are “shed” twice a year (once for breeding plumage and once for winter plumage in most species). Tag size ranges based on how long you want them to transmit; larger the battery, the longer the life.
I would like to share a few tips and tricks regarding nanotag attachment on shorebirds. These little guys change body shape during migration, putting on fat and losing fat quickly over a short time frame, and when I say get bigger I mean, almost doubling their weight in some species. So we can’t place harnesses on their body in the event the body shape and size change a lot. So we go with a “semi-permanent” external attachment aka, glue that bugger on. Here is how we do it:
Fiskar scissors; good quality!
Gel super glue, not the liquidy stuff
Your tags, tag activator, receiver to check that the tag is actually on
***Activate the tag, I do this before leaving my field camp and carry the activated tags in my bag with me for the day. It saves the trouble of carrying the gear for 20 km.
- Cut the feathers above the oil gland on the back of the bird leaving the strongest part of the feather (the base of the shaft) intact.
- Place glue on the tag, just a decent blob, enough of a blob it covers the back of the tag at the round end, label facing up
- Don’t glue yourself to the bird. To avoid this, I use something thin and solid to put slight pressure on the tag to the bird but not using my fingers.
- TAKE A PHOTO. This can be the only evidence of who is wearing what tag if there is data entry error or you forget to write it down. I have gone back and referenced photos with time stamps in case the tags weren’t right. So important.
**And what about those ROUND TAGS……..
It’s not convenient to glue a marble to a flat surface, which is what the NTQB4-2 tags feel like. So I buy a non-stretch, non-fray material, to help increase the surface to glue ratio.
- ACTIVATE the tag. If you glue anything to the tag before activating it, it likely won’t fit in the activator hole…..bad news bears
- Glue the mesh square to the tag
- Glue the whole lot to bird. Don’t be shy with the glue, the bird only wears it for a handful of weeks and with the cost of the tag itself, you want it to stick.
There are many ways of doing this and this is simply what works for me. I have not had problems with tags falling off and the extra mesh on the larger tags may even help prevent the bird from pulling the tag off. Good luck scientists and happy tracking!