January 19 - Winter Songbird Monitoring

This was our rescheduled day from the Sunday washout and conditions were beautiful. There was a big full moon setting on the horizon as nets were being opened, and a light frost shimmered in the rising sun as we opened the last net.


Bird activity seems to be shifting to earlier in the morning, with more birds caught on the first and second round, compared with the third and fourth round earlier in the winter. As mentioned in a previous post it could have been the colder weather earlier in the winter that had been causing a delay in bird activity. Now that temperatures are a bit warmer, bird activity has shifted back to around sunrise.

A Golden-crowned Sparrow and two Varied Thrushes (both recaptures) were our highlights from banding. About 20 Golden-crowned Sparrows have been present at Iona all winter, however, their activity has been concentrated along the fence between the woodlot and the sewage lagoons. They have now shifted their activity to other areas around the woodlot, including the open area in the centre. This shift resulted in one being caught and colour-banded. With their habit of foraging along the paths around the woodlot, this bird might be one of the easier ones to resight while birding.


Winter residents frequently show site fidelity their original wintering areas. In the late fall a Fox Sparrow originally banded in April, had returned to winter here. I have recently looked over the recapture history for our Song Sparrows to see if any might be returning winter residents, and it appears that five have returned. It will be interesting now to see if their departure dates are similar to last year, and how it will overlap with the arrival of spring migrants.

Two Yellow-rumped Warblers and the adult N. Shrike were still present on the 19th and when out on January 21st a Western Gull (new for the station) and Western Meadowlarks were found along the beach near the washrooms.

January 15, 16 - Winter Songbird Monitoring

The Pineapple Express has arrived and we were treated to balmy temperatures and unfortunately rain on Sunday. With all the rain we have had lately the water levels in the woodlot have continued to rise, with some areas now under 1m of water. We were able to open one of our nets in the north end of the woodlot as one of our volunteers saved the day and brought out hip-waders this weekend.


Overall catch rates are down a bit from early December, but we still caught ~30/day, with recaptures hovering around 50%. Its hard to say if the new birds are ones that have avoided our nets so far this winter, or if they are 'recent' arrivals. Some may be of the latter. This past weekend at least six Yellow-rumped Warblers seen around the sewage lagoons, and only two had been seen in December. It is possible that these birds may have been floating around the Vancouver area this winter and have recently made it to Iona Island, or they may have ridden the southerly winds up from points slightly further south.

Speaking of birds that may have ridden up on southerly winds, two species that I was hoping for and did not see this weekend were Barn and Tree Swallow. Most people would never think to search for these species in the middle of winter in Vancouver. But, since the 1990's many Barn and Tree Swallows have been seen every winter along the Pacific coast from California to BC. They typically arrive on southerly winds and generally don't stick around too long. No one knows exactly why they do this, but its not just these species that are traveling around at odd times of the year. Cave Swallows have in late fall for the last dozen or so years ridden low pressure systems from Texas and Mexico up to southern Ontario and the northeastern US, before following the eastern seaboard south again. So far this winter there have been several reports of Tree Swallows from both Washington and Oregon, a couple of reports of Barn Swallows and one report of Cliff Swallows in Oregon. Its only a matter of time before swallows are back in BC, so keep your eyes open for them in coastal areas such as Iona Island or the Reifel Migratory Bird Sanctuary.


Banding highlights this weekend were a recapture Varied Thrush, originally captured on December 31, our first new Marsh Wren since the fall, and another two American Robins (perhaps also moving around with the recent warm weather). All sparrows caught this weekend were still extremely fat, indicating that they are continuing to do quite well despite the rain. Other interesting sightings have included the wintering A. Bittern and Virginia Rails, two N. Shrikes (both of which were banded), a Rough-winged Hawk (new for the station!), and two Lincoln's Sparrows.

January 8 - Winter Songbird Monitoring

The ice and cold is gone, at least for now. Everything was back to its wet soggy self again, with the recent warm temperatures and rain having melted all of the ice that was present a week ago. It was really as pleasant of a day you could ask for in winter, the only problem we ran into (and for the first time) was a lack of birds. Only 23 birds were caught, however, what we lacked in numbers we made up for in quality.

Of note for those banders who will be coming out soon, is that with the switch over to the new year the age categories for birds have been changed. For those who aren't aware of how birds are aged, there are generally three categories that are used, young, adult and unknown, and the names for each category will vary depending on the time of year. It is easiest to picture things starting in the fall when most of the young birds of the year have fledged, these birds are known as hatch-year (HY) birds because they are in their hatching year. Their parents and other birds that did not hatch that year are known as after hatch-year (AHY) because it is after their hatching year. Unknown (U) is reserved for birds for which their correct age cannot be determined. Other age categories used are: local, for birds near their known nesting site, and third-year, fourth-year, etc. for various species which the adults can be more accurately aged than AHY, but we generally don't catch many of those species.

Now those HY and AHY birds remain as such all fall and up to December 31st. Starting January 1st the birds that hatched the previous year (formerly HY) become second-year (SY) birds because they are in their second calendar year of life, and the adults (formerly AHY) become after second-year (ASY) because these birds are in at least their third calendar year of life (ie. after their second-year). Unknown birds become AHY because at least in January-March most birds have not begun nesting yet and all birds will be at least after their hatching year. The terms SY and ASY will continue to be used until the summer we all of these birds will molt out all of their feathers and grow in new ones and we will not be able to separate these birds any more. Hopefully this will make a bit more sense of the ageing codes for everyone.


Now back to the birds! We managed to catch one new species for the station and observe two new species. We have been hoping that our nets along the edge of the north wetland might eventually catch a non-passerine marsh bird and we were finally rewarded with our first Wilson's Snipe! These birds spend the winter in decent numbers around the wetlands at Iona Island and it seemed like a matter of time before one of them would be caught. One neat thing with these birds is that their eyes are placed so far back on their head that they can watch you even when you are behind them.


The other new species for the station was a Cackling Goose observed flying over in a flock of Canada Geese shortly after net opening. Cackling Geese spend the winter in small numbers in the Lower Mainland, with a few being seen in the Vancouver area and more being seen in the agricultural areas further up the Fraser valley. The other new bird for the station was Snow Bunting that was both heard and seen flying over the station heading towards the south jetty, which is the location where they are most typically found at Iona.


The bulk of the days catch were the three usual species (Spotted Towhee, Fox and Song Sparrows), with an American Robin, two European Starlings, several recaptured Ruby and Golden-crowned Kinglets, Black-capped Chickadees, and a Bewick's Wren. Other interesting birds from the day were a Northern Shrike (likely the same adult from December), two Virginia Rails, an American Bittern, and at least one banded Varied Thrush (not sure when that bird was caught though).

One final note to keep you warm as we prepare for another snowfall, is that spring migration has begun! In the southwest a few Selasphorus Hummingbirds (either Rufous or Allen's) were reported moving north over the past week. The always early Purple Martin has been reported across Florida as well as singles in Texas and Georgia.

December 31 - Winter Songbird Monitoring

Temperatures had dropped considerably between the last time we were out banding and the 31st. A solid centimetre of ice had formed on all of the pools of water in the woods, which made getting to those nets considerably more difficult. At least we didn't have any snow to contend with. The wetland ponds were just about completely frozen over as well, with only a small area along the east side of the south pond remaining open and full of ducks. But we were treated to one of those few beautiful winter sunrises.


On cold days bird activity can take a little while to perk up and on the 31st it was no different. Only a few birds were caught until about an hour and a half after sunrise and most bird movement was noted after this time as well. The amount of energy needed to stay warm and move around foraging for food is probably greater than what they can gain through eating. So, for the songbirds wintering here it is probably more energy efficient to hunker down and wait for things to warm up.


It was also interesting to note that most of the birds caught had a lot of fat on them. We use a eight level system (0-7) to rate the amount of fat birds have on them. On migration birds can put on a lot of fat (typically 3-5), to be used as an energy resource to keep them going as they migrate. During the summer most birds are focused on nesting and then with replacing their feathers and most of their energy resources are put towards those activities instead of fat (typically 0-1). In the winter birds frequently put on enough fat (typically 2-3) to keep them through the night and/or through temporary food shortages caused by inclement weather. The birds must have anticipated it being a cold night and morning as most had 4-5 fat on them, with several having up to six.


Diversity was about average with 40 of the 48 birds caught were either a Spotted Towhee, Song or Fox Sparrow. Two of the most interesting birds banded most people wouldn't look twice at: Bewick's Wren (1) and Black-capped Chickadee (3). But we haven't banded a Bewick's Wren since August and the entire flock of chickadees in the woodlot had been banded, except none were seen except the three new ones. Also of note was another new Varied Thrush. This is the sixth one banded this year, all since November 21st, and none have been recaptured. It has been noted that this winter there have been higher than normal numbers of Varied Thrushes through the Vancouver area. Our banding totals likely reflect this and the lack of recaptures indicating that the habitat here isn't very suitable for Varied Thrushes. One final mention should go to the Northern Shrike that left a memorable mark on my thumb a few weeks ago. What is very likely the same bird (a banded adult shrike) is still being seen around Iona Island, primarily around the area west of the wetland ponds. It will be interesting to see how long this bird will stick around.