Prothonotary Warbler

Prothonotary Warbler

Thursday, 14 July 2016

Successful Acadians!

The Acadian Flycatcher seems to always have been a rare and somewhat local summer resident of southwestern Ontario. Eminent ornithologist with the Royal Ontario Museum, Jim Baillie, indicated that the first Canadian nesting record was in 1884, where a presumably authentic nest with three eggs was reported near Dunnville, in Haldimand County. However according to Baillie and Harrington, in their 1936 publication "The Distribution of Breeding Birds in Ontario", the species was only known to breed regularly at Rondeau Provincial Park. According to A. A. Wood's unpublished manuscript "The Birds of Kent County, Ontario", the first Canadian specimens collected were from the former Kent County back in 1909 near Renwick and Merlin, and the next two were collected from Rondeau Provincial Park by Baillie in 1933.


Suffice to say that field ornithology has made some major inroads regarding the knowledge of breeding abundance and distribution of Acadians in Ontario since then. The two Ontario Breeding Bird Atlases (1981-85 and 2001-05) as well as concerted field work by various people towards the preparation of status reports and recovery strategies for the species have given a much more complete picture of its Ontario range and abundance. Certainly it is still mostly restricted to the Carolinian Life Zone, especially where there are reasonably large blocks of deciduous forest such as Skunk's Misery in Middlesex County, Kettle Point First Nation to Port Franks area in Lambton County, and especially in Norfolk and the eastern portion of Elgin counties. It is designated an Endangered Species both provincially and federally.

It is still a regular breeding species of Rondeau Provincial Park where there is upwards of 1000 hectares of deciduous forest. In the right conditions in early June, some years it is possible to encounter as many as 8 singing males from the main roads. Who knows how many are back in along the ridges out of ear shot?

This spring, there were at least 4 pairs heard or seen from a road or trail during the breeding season. Three nests were visible from the road, although one right over the road was abandoned before any eggs were laid. I was particularly interested in following the activity of one nest. The previous year there was a pair in the same vicinity, and I am quite certain their energy was put towards raising a single Brown-headed Cowbird! This next image is the only one I got of that nest and it showed a young bird, looking very much like a cowbird.
The nest of the pair in this same territory in 2016, was right over a parking lot, making it very vulnerable to the influence of people as well as the parasitic actions of cowbirds. Even though it was well away from the technical edge of the forest, the road system allows for cowbirds, typically an edge species, to enter into the interior forest where nesting species such as Acadian Flycatchers would normally be a lot less vulnerable. So I wasn't holding out a lot of hope for this pair of Acadians to successfully raise their own kind, especially since I had seen cowbirds in the area.

I watched periodically using the car as a blind. An adult was almost always seen on the nest incubating.
At one point a couple of weeks after first discovering this nest, it was evident that there was at least one young in it, as this next image shows an adult removing a fecal sac.
A few days later, there was a head peering over the edge, with the beak of a sibling barely in view. In this next image, it seemed like the adult wanted to pose with its young.
As the young grew, it was clear that both of them were in fact Acadians! The dreaded Brown-headed Cowbirds had been avoided! This next image shows one of the young having just been fed a dragonfly, while its sibling was clamouring for its share.
The dragonfly proved to be a little more difficult to swallow than smaller fare, but it eventually got it down.
A few days later when I visited the nest, the young were getting close to leaving. They would stand on the edge and sometimes flutter their wings. I took this photo early in the day, and then went on to do other things.
Towards the end of the day, I decided to check on the nest again, and this time there was only one bird. The other had fledged, and I heard one or more of the adults in the trees nearby, presumably looking after the fledgling. Note that with only one bird left, and it is sitting on the edge of the nest, one can see right through the nest! That light area towards the lower right hand area of the nest is daylight....the structure is really quite flimsy.
No doubt this one was gone from the nest by the next morning, and now there would be two more Acadian Flycatchers to add to the population. Maybe one or both will successfully make the journey south in the fall and north next spring to continue the cycle. And hopefully the other nests in the park this year were equally as successful.












6 comments:

  1. Replies
    1. Thanks, Josh.....it is the first time in many years where the adults chose such an accessible location.

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  2. Excellent presentation Allen ! Thanks for sharing.
    I'm very pleased that the nesting was successful.

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    Replies
    1. Thanks, Irene. These opportunities happen so infrequently I thought it worthwhile to share it, especially when two Acadians fledged.

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  3. Wow! The dragonfly looks like a Blue Dasher from this angle.

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    Replies
    1. Thanks for your thoughts, Nate....I was thinking the same thing. I wonder how often dragonflies are used for food for these little ones!

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