In 1985, the Canadian Wildlife Service initiated a long-term monitoring program using the Red-throated Loon as an indicator of the environmental change that could result from offshore oil and gas development in the Beaufort Sea. Data were collected for five years at five study plots to obtain a predevelopment baseline measure of the abundance and productivity of loons in the region. Renewed interest in offshore hydrocarbon extraction prompted a second set of aerial surveys conducted in 2007 and 2008 at four of the five study plots. The same survey method was used, so that results could be directly compared to the earlier surveys.
There was little change in the number of Red-throated Loon resident pairs between the two survey periods at all four study plots combined (185 ± 19.3 pairs during 1985–1989 compared to 197 ± 36.8 in 2007–2008). However, when each plot was examined separately, the number of resident pairs at the Toker Point plot had increased by 28%. Productivity likewise remained unchanged at three of the four plots, with an increase occurring only at Toker Point. The marked increase at Toker Point was likely a result of depressed productivity during the earlier survey period (1985–1989) caused by disturbance from intensive searches on foot throughout the nesting season. The more recent measure of productivity at Toker Point (0.9 ± 0.2 chicks per resident pair in 2007–2008) is therefore more representative of the natural undisturbed state.
For results to be comparable across years, surveys must be timed to correspond with peak incubation period and dates when chicks are four to five weeks old. To address this problem we developed an equation that predicts timing of nest initiation based on the date when temperatures at Tuktoyaktuk reached 30 thawing degree-days. We recommend the use of this inexpensive non-invasive technique to ensure optimum timing of surveys.
As with most monitoring studies, consistency among observers is key to ensuring that the data are comparable across years. We recommend the following to minimize bias due to observer level of skill.
1) To the extent possible, maintain the same observers.
2) New observers should become familiar with relevant aspects of loon biology such as habitat types used for nesting territories and where the nest tends to be located within the territory.
3) New observers should familiarize themselves with past locations of loon territories at each plot, since Red-throated Loons tend to use the same areas year after year.
4) New observers and pilots should practice on a nearby wetland for one to two hours prior to starting the first set of surveys.
5) Resurvey part of two of the plots the following day to obtain detection rates for loons, nests and chicks.
Monitoring should be conducted for three years every eight years (i.e. three on and five off) until development is underway. More frequent monitoring will likely be required during the development phase so that negative impacts can be detected and mitigated in a timely manner.
Assuming the above measures are adopted, we view these surveys as a viable way of detecting changes in loon abundance and productivity, and thus recommend continued use of the Red-throated Loon as an indicator of the environmental change that may occur as regional hydrocarbon reserves are developed.
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