May 21st – Searching for the Cerulean Warbler

Male Cerulean Warbler

For me, the best time to be at Ruthven is in the early morning just after the nets are all opened. I pour a cup of tea, sit down at the picnic table just outside the banding lab door and listen to the dawn. The sun is not quite up but is painting the sky with subtle colours. Birds are singing all around: a Chipping Sparrow trills off to the right; the Purple Martins start up their sociable chatter; in the creek valley the fluting of a Wood Thrush competes with the songs of a Yellow Warbler and a Common Yellowthroat; way off in the distance, in the “reclaimed” farm land a Field Sparrow calls. It’s part of my job (and one of my pleasures) to hear them and mark them all down. But the one I was most anxious to hear was the song of the Cerulean Warbler, heard by both Nancy and Chris over the past couple of days.

Breeding and wintering range of the Cerulean Warbler - Cornell

This beautiful little warbler, which spends the winter on the eastern slopes of the Andes at an elevation of between 500 and 2,000 m, is in serious trouble. Its overall numbers have plummeted by about 82% between 1966 and 2007. In Canada there are estimated to be between 1,046 and 1,786 with a substantial majority of these being found in Ontario. At the time of the first Ontario Breeding Bird Atlas (1981-1985), it was found in 108 10×10 km squares; at the time of the second atlas (2001-2005), this had dropped to 86 10×10 km squares. Much of the decline is attributed to a loss of habitat in its wintering ground. Unfortunately, the elevation it prefers is the one most desired by humans: warm but not hot; too high for mosquitoes; good growing conditions. But there is also concern with the loss of habitat in its breeding areas. It requires large tracts of unbroken forest. In many areas its preferred habitat is riparian (riverside) forest – one of the rarest habitats in southern Ontario.

Last year, there was a singing male that stayed around in the forest across the highway from the Gatehouse. It would occasionally make forays into the forest along the creek on this side of the road. We were not able to determine whether there was a female with it. Could this be the same bird? [This was not the first Cerulean Warbler at Ruthven. There have been a number of sightings over the years and several years ago there was a singing male that stayed around in the vicinity of the graveyard for two weeks. It was with this species in mind that the Ruthven Board decided to take a wide strip of farmland out of production – land running adjacent to the forest along the Grand River. Along with this a ten-acre plot of agricultural land in the river flats was “let go” to revert back to riparian forest. If we can increase its preferred habitat, maybe, just maybe, we can help to maintain this bird.] We will continue to listen and look for this bird and try to ascertain whether it is nesting.

Female Blackburnian Warbler

It was a beautiful day: sunny, clear blue skies, no wind, warm, and NO rain. So, (as I’ve indicated many times before) it was a pretty slow banding day. Residents and breeding birds are busy competing for territories and mates (and know where the nets are by now) and migrants have flown over during the night making for the north shore of Lake Ontario, or even further.

Bluebird guru Bill Read holding a Sora found dead on Indiana Road. - R. Kinzie

Christine and Chris, in the course of doing their Tree Swallow work, found a dead Sora on Indiana Road, close to Brooks Road – so, on Ruthven property more or less. This is an area of agricultural land twisting around sloughs and wet spots – not really very good for farming. Some of the area has been taken out of “production”; hopefully more of it will be. Who knows what other water/marsh birds would be found in these wetlands?

Female Baltimore Oriole starting up a nest in front of the Mansion. - R. Kinzie

I’ve always marvelled at the hanging basket nests of Baltimore Orioles and wondered how they were made. By extraordinary luck I found a female in the early stages of construction high in a tree looking straight out from the front of the Mansion. Ruth Kinzie was able to take this amazing shot. It will be interesting to follow the progress of this nest over the next several days.

Banded 24:
1 Tree Swallow
5 Gray Catbirds
1 Warbling Vireo
8 Yellow Warblers
1 Magnolia Warbler
1 Blackburnian Warbler
2 Common Yellowthroats
2 Indigo Buntings
1 Song Sparrow
2 American Goldfinches

Retrapped 18:
1 Tree Swallow
1 Warbling Vireo
1 Nashville Warbler
6 Yellow Warblers
2 Rose-breasted Grosbeaks
1 Chipping Sparrow (there were not traps put out – hence the low number)
2 Song Sparrows
2 Baltimore Orioles
2 American Goldfinches

ET’s: 60 spp.

Today’s Photo Gallery (thanks to Ruth Kinzie):

Idyllic view of the Banding Lab - R. Kinzie

Male Common Yellowthroat - R. Kinzie

Male Magnolia Warbler

SY male Indigo Bunting - R. Kinzie

Female Indigo Bunting - R. Kinzie

Warbling Vireo - R. Kinzie


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