I think life around the field camp at Diabas this week was notable for its silence. Other than the wind flapping the tents or waves breaking on the shore, there was a deafening silence. Yes, the Summer for many birds is over. The Purple Sandpipers and Barnacle Geese have fledged their young. Occasionally you might hear the alarm call of a Snow Bunting, warning its chicks of the stealthy approach of an Arctic Fox or of a Parasitic Jaeger overhead, but they’re not singing. Really, it’s not until you’re almost right on top of the murre cliffs that you hear anything – and even their numbers have begun to drop as their chicks are beginning to launch themselves off the nesting ledges and into the water (and into a completely new life).
We were busy banding chicks and still trying to get adults and doing observations on particular birds as well as on their feeding behaviour – trying to get a sense of the types and number of fish they are bringing to their young and how often they’re doing it. This can be pretty difficult to do, especially as the chicks get bigger. The parent bird flies up to the nesting ledge with a fish held lengthwise in its bill. Almost immediately it gives the fish to its chick which swallows it whole, usually head first. This can take a matter of just seconds so…..was that a herring or a capelin or a polar cod? Hmmmm?
For the most part, it was cold and windy throughout the week with temperatures hovering around 2 degrees. (I understand that southern Canada has been experiencing a heat wave of late with temperatures that are up around 39 – without the humidex! I don’t know how I’m going to tolerate this temperature after the Summer here.)
The zodiac ride back to Longyearbyen on Friday was, perhaps, the nicest we’ve had so far – light winds and no waves; just cold…and it got colder the closer we got to town. Little did we know that this was because of a buid0up of pack ice along the coast just west of the entrance to Isfjorden. But more of this later. We were cruising along, about 200 m offshore when I saw a polar bear ambling along the shore. The first one on this trip! When it saw us, it broke into a bit of a trot. This is not usual polar bear behaviour and it began (probably) to overheat. It dealt with this simply – it went into the water and began to swim. We watched it for about 5 minutes and then left it alone; we didn’t want to stress it too much. The concerning thing though was that it was about halfway between the town and our campsite.
I had a chance to witness a couple of murre ‘fledging events’ this past week. In the first one, the young bird successfully made the jump into the sea with its parent right at its side. They, however, were accompanied by a large contingent (~80) of other adult murres that noisily surrounded them on the water. My first thought was that this might be a good thing as the others would help protect the young one from Glaucous Gulls, one of which was very quickly on the scene. While this appeared to be the case, there was something much more sinister at play: some of the extra adults were ‘mobbing’ or aggressively attacking the youngster while its parent put up an equally aggressive defense. Back in town I came across a paper by Grant Gilchrist and Tony Gaston in which they found that the single biggest cause of chick mortality at a large murre colony on Coats Island was this mobbing behaviour by attending adults. Evidently, an aggressive parent can often fend off the attackers, who will quickly lose interest leaving the young bird and parent to head out to sea. But often the attackers end up killing the chick. The reason driving this behaviour on the part of the attending adults is obscure.
In the second instance, I watched another youngster successfully land with its parent. They were quickly joined by another adult and headed for the open sea. Again, a Glaucous Gull was on the scene almost immediately, hovering overhead trying to grab the chick – at which time the adult would shield the youngster underneath its breast, wings outspread. When the gull was unsuccessful, it tried another approach: it sat on the water and began to swim slowly toward the chick and parent. When it got to be about a meter away, the two adults started to chase the gull. The gull flew away from the chick with the adults following but then, being much more manoeuverable, simply flew up and over the attacking murres and smoothly snatched up the chick, bearing it off to provide sustenance for its chick. It’s a tough world.
Yesterday, I spent back at Diabas finishing off the end of our chick bands. Fortunately, we had been driven out to the site in a large ‘polar circle’ zodiac. Our time there though was limited as the zodiac driver was VERY concerned about the pack ice that was being driven into the fjord by a strong west wind. The ride back to Longyearbyen, during which we had to rescue a family and their boat (that’s another story), was long, wet and very cold. And it became progressively colder the nearer we got to the ice. The trip back took 5 hours. [We got inundated with so much water that my camera, which was in a supposedly water-tight compartment on the boat, got soaked and rendered useless. So from here on I’m completely dependent on photos taken by my field team-mates.]
This morning we were supposed to zodiac back out to Diabas for our last week of fieldwork. It was a perfect day for it: light NW winds and cloudless skies. But….our way was blocked by pack ice and it was getting thicker each our as the wind had a westerly component -so, today we sat tight, filling our time with perfunctory but necessary tasks. Tomorrow there’s a good chance that we’ll be taken by helicopter to Diabas to complete the field season. I’m not sure how we’re getting back though……
Photo Gallery (thanks to Thibaut Petry):