Anne Murray: "Peep-In" showcases shorebird migration on Roberts Bank

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      On April 30, two Delta community groups, APE (Against Port Expansion) and CAPE (Citizens Against Port Expansion), are hosting their third annual “Peep-In”,  a celebration of the shorebird migration at Roberts Bank, near the mouth of the Fraser River in Delta.

      This event will showcase the spring migratory passage of millions of small sandpipers, known colloquially as “peeps”, and explain the threats facing them because of the Port of Vancouver’s plans to industrialize the area.

      About 50 different species of sandpiper of all shapes and sizes have been observed in the Fraser delta, yet the greatest number migrating through are western sandpipers. Roberts Bank is a traditional feeding and resting area for half the world’s population of these long-distance migrants and is absolutely key to their survival. It is part of Canada’s most significant Important Bird Area (IBA), as recognized by BirdLife International.

      Peep-In organizers anticipate that participants will see large flocks of these little shorebirds as they come in to feed at the high tide around 11 am.

      Western sandpipers winter in South America and make their way north to their breeding grounds in the Arctic by following an 11,000-kilometre route, often referred to as the Pacific Flyway, that brings them up the coast via Panama, San Francisco Bay in California, Gray’s Harbor in Washington state, and the Fraser estuary before arriving at the Yukon or Kuskokwim river deltas in Alaska.

      These shorebirds are only 17 centimetres long and weigh less than a granola bar, yet they fly, on average, 200 kilometres a day. One western sandpiper was clocked flying 3,000 kilometres from California to Alaska in less than 48 hours!

      When the peeps stop to feed on the muddy intertidal at Roberts Bank, they are, literally, fuelling up for the next stage of their journey. The muddy beaches around Brunswick Point are particularly rich in food, although what the birds were feeding on was, until a few years ago, quite a mystery.

      Many shorebirds push their bills into mud and retrieve amphipods, worms, snails, or molluscs. The longer the bill, the deeper they can reach. Yet it turns out that western sandpipers will often just slurp biofilm from the surface, a “snotlike” mucous secreted from bacteria and diatoms. This biofilm is extremely rich in nutrients and provides the calories needed for the tiny birds to make their onward journey.

      Typically, a flock of 100,000 sandpipers will consume 20 tonnes of biofilm, snorting up the snot with their hairy tongues at a rate of 121 times a minute. The discovery of biofilm consumption was made by researchers at Environment Canada and Simon Fraser University studying the shorebirds of Roberts Bank, and it has since been observed in other areas of the world.

      Biofilm is only available at certain intertidal areas, and it affects where peeps can stop and refuel. Brunswick Point at Roberts Bank is a particularly good location, as tidal saltwater mixes with freshwater at the mouth of the river and encourages the formation of biofilm on the mud bank’s surface. The peak northward movement of western sandpipers can be readily observed here in the last weeks of April and first weeks of May.

      Western sandpipers have a very short breeding season. Arriving in the Arctic in May, the female builds a skimpy nest on the ground and lays four eggs. Her chicks hatch fully feathered, able to run and to feed themselves. After a few days, she leaves them and heads south, arriving in the Fraser estuary from late June. The male stays in the north a little longer before beginning his southward migration, and the juveniles follow a month or so later, unguided by their parents.

      It is truly intriguing how these little birds can navigate from the Arctic to Central and South America without adults to lead them! With this drawn-out southbound migration, it is easy to overlook the passage of these little peeps through the Fraser estuary. In contrast, the spring migration taking place this month is more compact, with larger flocks and more urgency among the birds to move on after a day or two of feeding.

      Researchers have become pretty good at estimating the size of daily flocks at Roberts Bank (in the tens of thousands), but the overall population count depends on understanding how long each bird lingers in the same area. Often peregrine falcons and merlins harass the peeps, chasing them from one stretch of coast to the next. As a result, there is some controversy as to the total population of western sandpipers moving through the Fraser estuary.

      Most birdwatchers familiar with observing these birds during many decades argue that local populations have declined, just as shorebird numbers are known to have plummeted on most of the world’s flyways. Revivals in falcon populations have affected predator-prey dynamics, but massive habitat loss on shorebird migration routes allows these small birds far fewer options than in previous times.  

      Since the 1960s, the southward flow of the Fraser River onto the delta mud flats has been obstructed by the presence of two very long causeways leading to the B.C. Ferries terminal and to Deltaport, both of which have been widened in recent years. Artificial pods for loading coal and containers have been built at Deltaport, changing the tidal flow and other physical features of Roberts Bank. Electricity wires the length of the causeway are a hazard for flocks of birds flying across the delta.

      Also, the port construction has changed the intertidal environment between the causeways. One noticeable difference is the growth of Japanese and native eelgrass where there was previously mud and sand. Eelgrass meadows have their own ecological importance, with many species depending on them for nursery areas, but the loss of open mud flats is a negative impact for sandpipers, for which there was never any compensation.

      Farmland behind the dykes is also an important habitat for shorebirds sheltering at high tides and in stormy weather, especially where there is bare soil and puddled water. In the last decades, thousands of hectares of delta farmland have been converted to nonagricultural use.

      Habitat protection on Roberts Bank is incomplete. Steady expansion of port facilities took place through the 1980s and 1990s, in contradiction to the findings of a federal environmental-review panel in 1979 and Canadian Wildlife Service recommendations for habitat protection in an important report on the Fraser Delta’s birds in 1987. Recent developments that encroach directly onto intertidal areas include Deltaport’s third berth for container ships and the widening of the road and rail causeway.

      As well, Port Metro Vancouver (now the Vancouver Port Authority) is working on a new container terminal, Terminal 2, that would extend from the end of the existing causeway and double the size of the existing port; this project is currently undergoing a Canadian environmental-assessment process. Further development of logistic facilities is planned on farmland in this area. If constructed, T2 would have a highly detrimental effect on the ecological nature of Roberts Bank and would put at risk the globally significant flocks of western sandpipers—as well as many other wildlife species.

      Port expansion and its industrial infrastructure on the uplands has cast a pall over environmental conservation of this area of the Fraser estuary. The Roberts Bank foreshore was omitted from the 2012 announcement that extended the Ramsar international wetland site designation to include other notable areas such as Boundary Bay and Burns Bog. The Roberts Bank Wildlife Management Area only covers some of the intertidal, and a large piece was labelled “study area” on government maps, presumably to allow for further port expansion. The federal government must immediately take a sharp look at what is happening to the habitats of the Fraser estuary if they are to fulfil their international migratory-bird-protection obligations.

      The Peep-in on April 30 provides a useful reminder that Roberts Bank is home to many beautiful and unique species that rely on the ecological conditions of the Fraser delta. For more information, check out or