Wednesday, February 23, 2011

February 21 - Winter Songbird Monitoring

As we inch closer to spring, early breeding birds are busy singing and establishing territories, while later breeding birds have been concentrating in areas of food. Black-capped Chickadees and Marsh Wrens have become more territorial over the last week, with males actively patrolling territories and chasing away other males. American Robins, Song Sparrows, Bewick's and Pacific Wrens have all been heard singing more frequently than before. Grasses and other herbaceous plants along the paths have been greening up and providing food for Golden-crowned and Song Sparrows. The bud's on the willows along the west side of the woodlot have been increasing in size and insects have been congregating in this area as well. Yellow-rumped Warblers, kinglets, and chickadees have all been spending more time in this area presumably to take advantage of increased food availability here.


We managed to catch our second Myrtle Warbler in as many days of monitoring, this bird was a second-year male. The usual mix of both kinglets, chickadees, Spotted Towhees, Fox and Song Sparrows were present, the only 'different' birds were a Pacific Wren recaptured that was originally banded in November and a bright looking American Robin. Other birds of note are the same birds that have been seen all winter, including several Virginia Rails and the American Bittern.

It has been interesting comparing the variation in Fox Sparrows that have been caught at IIBO this winter, with most from the Sooty Fox Sparrow group, but several from the Red Fox Sparrow group as well. We managed to catch two this time that had characteristics of Red Fox Sparrows, such as white tipping to their greater and median coverts and a very rufous colour, but they did not have well defined reddish streaking on their backs. These are likely hybrids between the two groups, possibly from north-central BC, although without genetic testing we will never know. Compare the following photos of the two birds with a more typical Sooty Fox Sparrow.


Nearby at the Vancouver International Airport, a program has been started this winter to capture, tag, and relocate raptors to try and reduce the number of airline strikes, benefiting both raptors and travelers. To get to Iona Island you must pass by the airport and so it is worthwhile to check any Red-tailed or Rough-legged Hawks that you see for patagial (wing) tags. These tags will have a letter and a number to individually identify a bird. The bird below with tag C7 is a Harlan's Hawk (a subspecies of Red-tailed Hawk) that was banded in late January and relocated, but it has subsequently returned to the airport.

Thursday, February 17, 2011

February 13 - Winter Songbird Monitoring

There are not too many places in Canada where you have the opportunity to see, let alone band warblers in winter. Yellow-rumped and Townsend's Warblers regularly winter in small numbers in the Lower Mainland and on Vancouver Island. Wintering locations are most likely limited by temperature and food supply. Townsend's Warblers have been found to use backyard suet feeders, however Yellow-rumped Warblers feed on a more natural mix of insects and berries. As a result Yellow-rumps are found more frequently found in coastal areas, where temperatures are more moderate and insects can usually be found throughout the winter. Iona Island is one of the few locations where Yellow-rumps have been found reliably in winter. This is likely because of the moderating influence of the ocean and the relative abundance of flying insects around both the sewage lagoons and wetlands.

This winter up to eight have been found at Iona and all look to be adult males, with an equal split of Myrtle and Audubon's subspecies. At least one or two have been teasing us all winter by flying just above the nets. Recently, though, the entire flock has been spending more time near the nets in the willows at the edge of the woodlot. Possibly as a result of this, at our last monitoring session we finally caught one!


The bird was an after second-year male Myrtle Warbler. It will be interesting to see now that the flock is spending more time around the nets if more will be caught, and if they will return next year. Other interesting birds around included a recapture Varied Thrush (originally banded in late November), a Spotted Towhee (last seen in April), and a Cackling Goose in the sewage lagoons.

Thursday, February 10, 2011

February 8 - Winter Songbird Monitoring

Spring has sprung! ...or at least it has started. The Red-winged Blackbirds around the wetlands have been a little vocal over the winter, but this time they were in full song and defending territories. Canada Geese have also gotten into the act, by pairing off and becoming more aggressive towards other pairs. Pacific Chorus Frogs continue to be heard calling, although we have heard them here in every month of the year. Reports from Portland indicate that the first wave of spring migrants have come in, with Say's Phoebe, Turkey Vultures and increasing numbers of swallows (Barn, Tree, and Violet-green) all reported recently. It won't be too much longer until a few of these reach southwestern BC.

One continuing trend is the burst of activity during the first hour of the day, starting half an hour before dawn. We managed to capture 21 of the 27 birds caught today within this first hour, and the remaining six birds were caught on two nets runs over the rest of the morning. Several birders and photographers in the area also noted the absence of bird activity mid-morning. Interesting birds that were caught included a returning Song Sparrow and Spotted Towhee that were banded last April and had not been caught again until now, a Golden-crowned Sparrow first banded in late November and a Pacific Wren first banded in mid-November. Looking at this winter's data so far, it appears that there may a population of around 40-50 of each Spotted Towhee, Song and Fox Sparrow, and probably 10-15 Black-capped Chickadees and Ruby-crowned Kinglets, and 5 Golden-crowned Kinglets.

Other observations included many waterfowl in the sewage lagoons, with the bulk consisting of Northern Pintail, Northern Shoveler, and Green-winged Teal. Six to eight Yellow-rumped Warblers (both subspecies) were seen hawking insects in the cottonwoods on the west side of the lagoons. These are likely the same birds that have been present all winter, but they can be tough to find at times.

Now that we are nearing the end of the winter period it will be interesting to see when our birds leave and when the first wave of migrants will show up. It can't be too far off...

Friday, February 4, 2011

January 29/30th - Winter Songbird Monitoring

A slow weekend allowed us to take care of some site maintenance, namely building a roof for our banding table! Shawn Hilton came by on the 30th with tools and wood to put together a roof, with a little help from us, to provide us some protection from the elements. Slowly one step at a time the banding table is evolving into fully fledged station.


As mentioned before things were slow during this monitoring period. A total of 33 birds were captured, 22 recaptures and 11 new birds. Captures were dominated by Fox Sparrows (13), but also included Song Sparrows (10), Spotted Towhee (4), Ruby-crowned Kinglets (2), Golden-crowned Kinglet (1), Black-capped Chickadee (1), Bewick's Wren (1), and Golden-crowned Sparrow (1). A number of Song Sparrows have gotten wise to the nets and were observed flying under and around the nets. This indicates that colour-banding can be quite useful, as a number of other birds were observed well away from the nets and provide valuable survival information. One lonely Yellow-rumped Warbler, two Northern Shrikes, and one Canvasback were also noted around the banding area. Also of note for those remember from one of the previous posts regarding swallows, several have now been seen in the province including two Barn Swallows at both English and Boundary Bays and two Tree Swallows and one Barn Swallow at Swan Lake near Victoria. It will only be a matter of time before they are back at Iona Island again.