OYSTERCATCHER PARENTING

The British Columbia Coast takes the full force of the prevailing westerly winds. In summer, the westerly along the south coast pumps nutrients from the ocean depths into surface waters creating a rich plankton meadow floating at sea. These plankton are the source of food for the myriads of intertidal animals that inhabit our shores. Nearly every rocky shore has its resident population of mussels that sieve the plankton and, limpets and chitons that graze the seaweed clinging to the rocks. And where there are limpets, chitons and mussels, there are usually seashore dwelling Black Oystercatchers.

There are about 11,000 Black Oystercatchers along the north Pacific and about half are found in British Columbia. Raising young oystercatchers through the perils of seashore life often ends in failure. Recent research by Stephanie Hazlitt at Simon Fraser University shows that nesting is arduous with few oystercatchers surviving to become adults and she suggests that oystercatchers have adopted an insurance policy when it comes to raising their young. Some nesting territories have much better feeding areas than others - prime real estate for an oystercatcher is a low sloping beach with lots of the oystercatcher's favourite prey of limpets, chitons and mussels. Parents on not-so-good territories lay the standard three egg clutch even though their territory might not have enough food to raise them. Why should they lay more eggs than they can raise? One suggestion is that the additional egg is an insurance against the loss of the first or second egg.

Oystercatchers often nest on small rocky islets away from most predators. They can be sensitive to disturbance and will let you know in no uncertain terms. Oystercatchers have a shrill "eeek" when alarmed. Well-meaning boaters and kayakers are often the worst offenders. Do your part by avoiding these sites and watch from a safe distance.

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