May 30th was probably one of my top 5 most enjoyable days of fieldwork since Frontenac Bird Studies began. The weather was perfect, the biting insects were oddly subdued and I could scarcely walk 100m before needing to georeference some exciting critter. I saw many butterflies, moths, snakes and plants of note but the centerpiece was a wetland that Steve Gillis and I explored during our first biothon in July 2010. Below are two panoramic views of the swamp from the south and east respectively (click to enlarge).

The wetland is fairly large by frontenac standards, about 9 acres in total area. It is distinctive in having a small raised island of live trees (mostly pine) surrounded by a flooded lowland dotted with snags and fallen trees. Surrounding the wetland is mid-successional oak-maple forest with scattered mature trees, an open understorey and with ground cover dominated by grass. The area was absolutely teeming with cavity nesters – Northern Flickers, Hairy Woodpeckers, Yellow-bellied Sapsuckers, Great Crested Flycatchers and White-breasted Nuthatches mostly. Apparently the area is so irresistible to Common Grackles that they were also nesting in cavities 10-15m above the water – an unusual choice for them (1.8% of nests reported to Ontario Nest Records Scheme n=2652).

At the far north end of the swamp were two large platform nesting species – Osprey (1 nest) and Great Blue Heron (3 nests). These and the all the cavity dwellers put on quite a show! The bordering woodland was also active with Cerulean Warblers, Red-shouldered Hawks, Yellow-throated Vireos and a single Olive-sided Flycatcher being the most noteworthy. The Olive-sided is the first I’ve seen in the region and probably a migrant, although suitable is available north of the park closer to highway 7. You can hear it singing in the video clip above (quick-three-beers) along with the odd Cerulean Warbler.

The birding at this site in July of last year was less memorable, probably due to the fact that it was during a mid-afternoon in July. However we did spot a pair of Red-headed Woodpeckers that day (Melanerpes erythrocephalus) – a rapidly declining species (Threatened status) in Ontario. It turns out that the species has been retracting from many parts of its range but heavily in Eastern Ontario. Our observation was the second of only two documented breeding records for Frontenac Provincial Park, although breeding evidence was not officially obtained in 2010. I bookmarked this as a target for 2011 and am pleased to report that it took me less than 30 minutes to confirm an active nest site this past Monday!

Their active behaviour and brilliant high contrast of their plumage made them easy to track and observe within the open wetland. An adult called repeatedly from the west end of the swamp but rarely approached the nest (the male?). The other adult, presumed to be the female, made frequent trips to a cavity near the top of a 14m tall snag close to the southeast shoreline. The video at the beginning of this post highlights some of the activity at the nest site, which seemed to be exclusively short incubation sessions as no excavation or food carrying were noted. We will return to this site again in the next week or two to check on its progress.

The Red-headed Woodpecker is an extraordinary bird for many reasons. This post is already running long so I’ll have to return to this topic at a later date to highlight its unique ecology and relationship with human settlement. Below are two instructive breeding evidence maps from the Ontario Breeding Bird Atlas, which visualize the widespread decline of this species in Southern Ontario. For further intormation, The Birds of North America account (subscription needed) is essential reading for this species but the Cornell account hits some key points too.