Cooper Island, Alaska, July 7, 2009 — I arrived at my field camp on June 15 having chartered a helicopter from Barrow, Alaska, 25 miles west of Cooper Island. The days just before the field season started were full of the typical mixture of excitement for the opportunity to return to this remote Arctic island coupled with the apprehension that comes from knowing that if some critical piece of equipment is left behind one would have to get by for weeks before resupply is possible. This year a critical piece of communications equipment needed to be repaired, which is the reason this is the first post from the island.
In late June and early July my daily field activities consist of taking a census of the colony to see if the birds that bred last year have survived the winter and retained the same nests and mates, and then conducting nest checks of the approximately 200 nests boxes on the island. This year egg-laying for black guillemots started on June 18 and is just coming to an end on July 2. The weather during the first week of egg-laying was unseasonably cold with temperatures below freezing on most nights and no higher than the mid-30s in the afternoon. Because guillemots lay a two-egg clutch and incubation does not start until the second egg is laid, typically three to four days after the first, early nest checks typically mean finding the first egg of a clutch sitting unattended on rocks or sand and exposed to subfreezing temperatures. Apparently all birds have the capacity to suspend early embryonic growth when eggs are chilled but most don’t regularly experience subfreezing temperatures, as do the black guillemots on Cooper Island. Now that egg-laying is complete, parent birds are constantly attending the eggs, which they will incubate for approximately 28 days before hatching.
The Arctic pack ice is still up against the north side of the island and breakup appears to be progressing more slowly than recent years, but I will know more about that by my next post.