By Geoff York
The morning breaks the same as the day before and, once again, it is hard to say which way the weather will go. We’ve had some fresh snow overnight and the temperature is hovering right at -16 C with a wind chill of about -23 C. Winter never completely leaves this far north region as they can see snow during every month of the year!
The first couple of hours flying are fairly uneventful. The helicopter we are using this year has an operational limit of about three hours per fuel load. The fixed wing fuel support allows us to work for the better part of a day, especially if we are catching bears and spending several hours on the ice. Finding a spot where the plane can land and transferring the fuel can take a bit of time as well. You would be surprised how few flat areas are out here some days!
Speaking of time on the ground – what do we actually do once we safely sedate a bear on the ice? The FWS tries to minimise the stress of capture events and maximise the information obtained from each animal handled. This takes a great deal of care and time in practice. It also involves collaborating with other agencies, NGOs, and universities to maximise the data collection and analysis possible from such work.
As soon as the bear begins going under the sedative, we make sure they are going down in a safe place and position (nose out of any deep snow). Once the bear shows signs of complete sedation, we approach on the ground. The first thing we do is to check the dart and assess the amount of drug injected. You want to know how much of the sedative was injected before you get too comfortable!
As one biologist checks and removes the dart, the other takes a set of vitals, both temperature and respiration, to make sure the bear is not too warm following the darting run. Later in the season, this becomes more of a concern as temperatures don’t have to warm much to be considered ‘hot’ to polar bears. If a bear is hotter than we’d like to see, we carry water to wet them down and can also pack them with snow and get them in a position to dissipate heat. Overheating is typically not a problem capturing bears on the sea ice in the spring.
While the bears are most relaxed, we take a series of measures including bioelectrical impedance (BIA) to assess percent muscle mass, various length and girth measurements, and a suite of biological samples. Scientists are looking at various measures of animal condition and health as well as feeding ecology (who’s eating who).
Eric Regehr of the FWS checks for a tattoo while I log vitals data. Three of our least favourite tasks, but among the most important, are applying marks to the bear and collecting a small tooth. Every bear is given a number and this is applied in four places – two ear tags, and two lip tattoos. Multiple marks are applied as bears can lose ear tags and tattoos can become illegible over time. Between them, we can generally identify marked animals when we see them in future years. This is important to learn about animal survival, reproductive history, growth, and condition over time. It is also imperative for estimating population size.
Two of the last things we do are weight and a final paint number. Both the FWS and USGS polar bear research teams routinely weigh every bear they capture. We carry a collapsible tripod, a large net, a crane scale, and an engine hoist to accomplish the task. The largest bear weighed this year, and this may be the largest ever physically weighed in the wild, came in at 614 Kg (and this bear will weigh even more by the end of summer)!
614 Kg Male polar bear in the Chukchi Sea (Photo by Eric Regehr, USFWS) Right before leaving the capture location, we use non-toxic fur paint and give the bear a season number. We do this for two reasons: one is to apply a visible mark that AK Native hunters can readily see that this is an animal that was recently handled; and secondly so we can identify them from the air and not bother them again this season. During the course of a season we may also get data on cub survival if we re-sight family groups over the 6 week period.
Late in the afternoon we get the chance to go through these procedures on two spate captures of adult male bears. The second male was a “teenager”, likely between 6-8 years old and had been following, and interacting with, a mother and yearling we had previously captured. He was a little worse for the wear as the sow had landed deep scratches on his shoulders and neck and a few canine punctures on his head! Not too pretty, but not unusual for bears this time of year trying to breed, fight for the right, or in this case, hitting on the wrong lady. It was one of the few times I thought capturing a bear probably did him a favour as he was still pursuing the tracks when we found him. He was nothing if not persistent.
WWF International Arctic Programme polar bear specialist, Geoff York, is currently in the Chukchi Sea area with the US Fisheries and Wildlife Service, conducting research into the status of polar bear populations in the area, and is blogging for the WWF Climate blog while he is there.