Kejimkujik

Common loon

© P. Hope, Kejimkujik N.P.

The common loon is a large waterbird found on wooded lakes across Canada. It's black and white in colour, with startling red eyes. Loons are featured on the Canadian $1 coin — which has become affectionately known as a 'loonie'.

Common loons are slow on land, but are powerful swimmers and divers — they can dive to 15 metres. Once airborne, they are swift fliers. Babies can swim as soon as they hatch, but are often observed, in their first few weeks, riding on an adult's back.

Common loons have four very distinctive calls:

• Hoot — used for keeping in contact.
• Tremolo — an alarm call, which has been described as 'insane laughter'.
• Wail — a contact call, heard in the evening or at night.
• Yodel — a territorial call made by males.

The birds' courting behaviours involve much splashing and frenzied running across water, which may have led to the expression 'crazy as a loon'.

The Canadian Wildlife Service conducted a survey of common loons on 40 lakes in Kejimkujik National Park between 1988 and 1997. The total loon population remained relatively stable over this time, with approximately 39 resident pairs. The number of chicks hatched varied between 5 and 18 a year over the study period.

Overall, Kejimkujik's loons have a lower reproductive rate than other North American populations. Blood samples taken from Kejimkujik's loons showed that they contained high levels of mercury. Samples taken in 1995 and 1996 revealed among the highest blood mercury concentrations of any loon population in North America. It is thought these high mercury levels are related to the loons' low reproductive rate.

The results of the survey amounted to an early warning sign and a larger study on mercury contamination in loons, fish and water is being undertaken.