Hi Tweets,

Following with great interest the Common Tern/Bonaparte's Gull thread.

Yesterday, I was prepared to join in the general moan about how Bonaparte's
Gulls and Common Terns are dropping from the radar, and then went out and
saw the biggest flock of Bonaparte's Gulls I've seen in ten years off the
south side of Burrard Inlet, nearly 100 Def Basic birds. But this also
raises a question.

In Stanley Park littoral recently, there seems to have been a change in
Bonaparte's Gulls' post-breeding distribution since the early 1990's.
Whereas they used to be common when the breeding adults returned to the
coast in mid-July and rejoined the summering 2nd Year non-breeders loitering
around the inlet, particularly at the Locarno Crab Pier, and a pile of
juveniles began joining the mix about two to three weeks later, now we don't
see 'em nearly as much in the Stanley Park (and can we generalise out to the
rest of the inlet itself?) littoral until mid-October, when their numbers
increase significantly. And then they're mostly Basic-plumaged adults
instead of the mostly Juvenile/1st & 2nd Year birds you'd expect. What's
with that? Have they found another migration route?

And what's happened to the Common Terns? This used to be a bird we'd see
daily in the 20-50 range every day along the Stanley Park Seawall in Aug/Sep
often with 1-2 Parasitic Jaegers tagging along behind. More along West
Spanish Banks, where typical COTE (and occasionally a few Arctic Terns)
numbers were 50-100 with anything up to 5 individual Parasitic Jaegers of
all age-groups were average until the mid-1990's. Now, there's little to
nothing. What's changed? Nobody seems to know.

And in the late 1980's and early 1990's, I noticed there was a small but
noticeable decline in the seabirds observable from the S side of Burrard
Inlet, a decline which became more marked as the decade wore on. A slumping
in the numbers of Marbled Murrelets was the first obvious sign something was
up. One day in the early 1980's, with ideal observing conditions, I was able
to count 55 pairs---pairs!--of Marbled Murrelets in the outer section of
Burrard Inlet from Stanley Park's Ferguson Point. By the mid-1990's, there
were none in that section: I know that because I was then involved in
boat-surveys of Burrard Inlet for those five years in the mid-1990's: at the
beginning there was a handful that dwindled down to none for the entire
outer part of Burrard Inlet: False Creek and Lion's Gate to Point Grey and
Point Atkinson, including the Grebe Islets. The proximate cause of their
extirpation was clear-cut logging of their old-growth nesting habitat in the
Vancouver water-districts. Why was there no push for their protection and
conservation? I don't know: you'll have to ask the Canadian Wildlife
Service, Greenpeace, the Western Canada Wilderness Committee and Nature
Vancouver (the re-named Vancouver Natural History Society) why there was no
outcry, since it disappeared from Vancouver waters on their watch. In any
event, the murrelets are now extirpated from the outer section of Burrard
Inlet.

The murrelets were just the start. Over the same decade we've seen
significant declines in certain gulls, terns, jaegers, waterfowl, grebes,
loons and alcids.

So, one day, just for gallows-humor fun and trying to see if there was an
unifying factor, I made a list of all the birds in Stanley Park which have
gone from very abundant and very common, regular every-day wintering species
in the 1960's, 1970's and 1980's which are now uncommon to rare to
completely absent. Here is that list. There is, when you think of it, a
unifying factor.

1970-80 present

Common Loon fairly common uncommon to rare
Pacific Loon fairly common rare
Red-throated Loon common rare
Horned Grebe very common fairly common to
uncommon
Red-necked Grebe uncommon rare
Western Grebe very abundant uncommon
Ruddy Duck common rare
Greater Scaup common uncommon to rare
Lesser Scaup very abundant fairly common to
uncommon
Black Scoter locally common rare
White-winged Scoter uncommon uncommon
Surf Scoter very abundant locally
abundant to common
Long-tailed Duck uncommon rare
Barrow's Goldeneye locally abundant locally common
Bufflehead common uncommon,
common transient only
Red-breasted Merganser very common fairly common to
uncommon
Black Turnstone locally common uncommon, common
transient only
Dunlin common winter, abundant transient rare winter, uncommon
transient
Sanderling common winter uncommon to rare
Semipalmated Sandpiper common juv migrant very rare
Western Sandpiper common juv migrant very rare
Least Sandpiper common juv migrant very rare
Parasitic Jaeger uncommon migrant very rare
Bonaparte's Gull common summer and fall uncommon
Common Tern very common rare
Caspian Tern common fairly common
Common Murre common offshore undetermined
Pigeon Guillemot fairly common uncommon
Marbled Murrelet common extirpated
Rhinoceros Auklet uncommon to rare rare

all, except for Barrow's Goldeneye which feeds on mussels and barnacles,
feed on small fish. If, for whatever reason, there's been a collapse in the
baitfish populations, all these species would be hit. And why would this
fishery collapse?

Well, there's pollution. In the mid-1980's, the City of Vancouver stealthily
dumped many thousands of tonnes of toxic soil from the Expo 86 site in False
Creek off Point Grey. There's the ocean-going freighters which moor where
the Western Grebe flock of 8,000-12,000 used to winter before we turned that
part of Burrard Inlet into a freighter parking-lot with all its attendant
discharges (it's an open secret that Canada has one of the most lax
regulatory regimes in the world when it comes to polluting freighters).
There's possible warming of the ocean, which could cause a collapse of
certain fish-species. There's overfishing, and the fishermen are moving down
the food pyramid, catching one smaller species after another as they
extirpate the big fish. There's a huge by-catch of seabirds in BC seining
and gill-netting (one observer was threatened with a huge libel-chill suit
if he went public with his observations).

But there's also destruction of nesting habitat in the boreal forest by
clear-cut logging and beetle infestations. Gee, let's see, what else could
go wrong? What's that, Colonel? An asteroid is about to hit Burrard Inlet?

Michael Price
Vancouver BC Canada
loblollyboy at gmail.com

"I feel like a fugitive from th' law of averages!" -- GI Willie
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