By Anne Murray
The first Delta History Hunter trip of the year was a visit to the Great Blue Heron colony on Tsawwassen First Nations lands at the end of the ferry causeway. Fourteen of us gathered to view springtime activity at the colony, the largest in the lower mainland. I gave a short talk on the history of the heron colony and some details of their life cycle, and this was followed by Angela Husvik and Joannie Bennett showing some archival photographs and reminiscing about life on the beach in the days before the ferry and port developments.
We were initially fortunate with the weather, as the sun shone on us as we watched the prehistoric-looking herons gliding overhead and standing tall in the shallow water of Roberts Bank. The maple trees were in full leaf so it was a little difficult to see the nests at first, but by sharing binoculars everyone eventually got a good view of herons carrying sticks, standing on the nests, and squabbling with each other. An eagle sailed overhead setting up some squawks of alarm and frogs croaked in the ponds beneath the bluff.
After my presentation on the herons and some time just spent watching and enjoying the activity, we moved around the corner intending to walk a little way down the beach. However, by that time the wind had got up and it was quite cool, so we gathered in a sheltered corner of the grass to look at archival pictures Joannie had brought showing the early building of the ferry causeway. She and Angela remembered coming down to swim at the beach with their families, collecting clams and crabs and generally enjoying what was then a quiet remote area of the great delta landscape. The group discussed the changes that the causeways and other developments had brought to the ecology of Roberts Bank, blocking the water flow southwards, and affecting the fish and shellfish.
Eventually the cold wind got to us, and we decided to continue our chatter at Petra’s coffee shop in Tsawwassen, with most participants spending a lively 40 minutes or so there. It was good to see everyone again, after the winter break, and the turn out was amazing considering I only sent the email around two days before (due to being out of town for family circumstances). Next month, May 22, we are invited to Anne and Martin Hamming’s farm near Crescent Slough, Delta. Check for details on the DMAS website. I hope you will join us.
Some notes on the Great Blue Herons of Tsawwassen Bluffs
From 1973 to 2004, the main Great Blue Heron colony on the peninsula was at Point Roberts. It had 350 nesting pairs and was considered the largest colony in the Pacific northwest at the time. Delta History Hunters’ participants remembered colonies in the 1950s and 60s on Cliff Drive and Raitt Road (now 12th Avenue) and on the bluffs above Boundary Bay. A photo in the DMAS Archives shows a tree with nests on Raitt Road.
In 2001, a golf course was built adjacent to the heronry in Point Roberts and some trees were cut down, although the land on which the heronry stood was purchased and protected. Around the same time, the burgeoning Bald Eagle population really took off, and the higher number of young eagles around caused changes in behavior. Juvenile eagles began to attack herons at the colony. Herons are notoriously skittish about noise and disturbance and while they managed to hang on through the breeding seasons of 2002 and 2003, by 2004 it was all too much. Some had already left, and in June, the colony suddenly abandoned overnight, leaving behind eggs and chicks.
The herons settled at the new site in 2005, the bluffs just a couple of kilometers along the coast on Tsawwassen First Nations land near the end of the ferry terminal causeway, close by the Tsatsu Shores condominiums. These bluffs are well-wooded with bigleaf maples, alder and Douglas-firs and have a resident pair of adult Bald Eagles to guard against roving juveniles. The heronry is set back from the side road by a damp, marshy area, an excellent buffer against human disturbance. The large trees are able to support multiple nests – ten or more in a tree is not uncommon. Stands of trees this size are scarce on the shores of the lower mainland and the Tsawwassen bluffs are a very important location for this species. Great Blue Herons on the Alaska, B.C. and Puget Sound, Washington, coast belong to the subspecies Ardea herodias fannini, aslightly smaller and darker subspecies than the more widely distributed Ardea herodias Herodias. It is listed as a Species at Risk and there are only about 8,000 in the total population, half of which are in B.C., with the majority in the lower mainland, southern Gulf Islands, and southern Vancouver Island. The colony at Tsawwassen Bluffs may have about three hundred nests.
Herons are sometimes called “cranes” but the Sandhill Crane belongs to a totally different family. The Great Blue Heron is a tall wading bird with a sinuous neck, long legs and a long black crest. The crown is white in adults, grey in juveniles. Male and females are alike, although males have a longer bill. Herons are surprisingly light as they have hollow bones. Powder down feathers on their breasts help with preening and keeping their plumage waterproof. Great Blue Herons are resident on the coast, but only come to the nesting colony between early March and July, after which they disperse to the mudflats and fields of the delta. They will eat fish, voles, frogs, bullfrogs and snakes.
Their seasonal cycle begins when the weather warms up in early spring and the fish move into shallow water nearer the beach. The herons beaks turn orange as a sign of being in breeding condition. Juvenile herons take about 3 years before being ready to breed. Males and females are monogamous for the season but may choose a different mate the following year. Both help with building the stick nests up in the trees, lining the nest with other vegetation. The nests are rather flimsy and generally rebuilding is needed after the winter. Usually no more than one, or at most two herons are raised.
The colony becomes pretty dirty and smelly by the end of the season, with copious guano, fish remains and dead chicks. The trees turn grey with the droppings, but the nitrate also provides fertilizer. In spring the forest greens up as usual. However, herons may move their colony periodically, whether or not they are disturbed, as the trees take their onslaught. It is very important that treed bluffs and forest areas are retained on the peninsula to allow for the natural growth and periodic movement of heron colonies, to ensure the future of this fascinating local bird.