North Water Polynya Seabird Surveys

To relate avian usage of the North Water polynya to the distribution, abundance
and production of prey, we assessed seasonal changes in the distribution and
relative abundance of seabirds. In order to assess the spatial distribution of
seabirds in the North Water, we conducted surveys of seabirds from the bridge
of the Canadian Coast Guard icebreakers whenever the icebreakers were underway.
Bird specimens were also collected to carry out stable isotope analysis.

The purpose of this study was to assess the patterns of avian usage of the
North Water polynya. We assessed the timing of arrival and the seasonal changes
in the at-sea distribution of seabirds in the North Water polynya and related
these parameters to oceanographic conditions. Oceanographic variables were
collected by collaborators and are not part of this data set.

Birds were counted from the bridge of a ship within 300m one side of the ship
whenever the ship was underway. Weather conditions and ocean conditions were
recorded simultaneously and it was noted when sightability decreased to less
than 300m. Position was recorded from ships GPS. Strip width was regularly
checked using the Heineman method (Heineman 1981). Ship speed and course and
position were recorded regularly. Birds behavior (flying, sitting on the water,
feeding) were noted for each bird sighting. Some inconsistencies in the
estimation of how much area was surveyed (based on ships speed and course) when
ship changed course to avoid ice or had to back up to crash through ice.

We conducted surveys from the bridge of Canadian Coast Guard icebreakers
whenever the icebreakers were underway; the CCGS Louis St. Laurent in August
1997 and the CCGS Pierre Radisson in April-July 1998 and August-September 1999.
We counted all birds within a 300m wide arc from the bow on the side of the
ship with the best visibility. Data were entered directly into a notebook
computer by the observer. We determined the boundary of the area in which the
birds were counted by using the method of Heineman (1981). We noted the birds
behavior (Flying, sitting on the water, etc). as well as the ships speed and
course. As each bird sighting is entered into the computer, a time stamp is
given to each record.