The Ravens Have Landed!
By Ken Dance
You no longer need to travel to the Canadian Shield or Bruce Peninsula to hear the raucous croak of our largest songbird. Since Spring 2011 Common Ravens have invaded and seem to be settling in a number of counties in Southwestern Ontario, including Oxford.
At the January 23, 2012 K-W Field Naturalists meeting ravens were reported from Baden and it was indicated that 2 ravens had been seen during the Linwood Christmas Bird Count (CBC). At that KWFN meeting, Bill Tilt told me that he had seen a raven at Wrigley’s Lake, RM of Waterloo, during Autumn 2011.
Bill Wilson has indicated (in a personal communication) that ravens were first sighted at the rare Charitable Research Reserve in Cambridge/North Dumfries on May 13 and subsequently on October 16, 2011.
The Cardinal, the newsletter of Nature London (The McIlwraith Field Naturalists of London Inc.), reports in the April 2012 edition that a raven was observed in London on March 19 and April 30, 2011. No Common Ravens were reported, however, during the 2011 London, Woodstock, Ingersoll or Stratford CBCs (The Cardinal No. 226).
My family (Janet and Kevin) and I have observed Common Ravens on twenty one dates in Brant and/or Oxford Counties (R.R. #1 Drumbo) and/or Waterloo Region near Ayr during every month of 2012 from January (5th) to September, inclusive, except March and August. Frequently two ravens were seen together and on two dates, June 18 and 21, six Common Ravens were seen together in a flock. I hypothesize that this was a family group containing fledged young.
All of our sightings were within 1km of the Nith River Valley. Many observations were of ravens leaving agricultural fields and disappearing into the woodlands along the river valley.
Evidence of probable breeding in Oxford County in 2012 is as follows:
(1) nuptial flight of a pair on February 4, 2012 above 807566 Oxford County Rd. 29 (R.R. 1 Drumbo);
(2) consistent sightings of a pair in the area of the above-noted location: January 5 through June 17, 2012;
(3) sighting on June 18, 2012 of a group of 6 ravens, some were feeding on the ground in a harvested grain field with others on guard in a nearby tree – several of the birds on the ground seemed to be “awkward” when initiating flight; and
(4) when the group of six flew away there seemed to be larger and smaller individuals, as well as leaders and followers.
On June 21, 2012 the group of 6 ravens was seen again.
A brief comparison of the breeding range of the Common Raven in the first and second Ontario Breeding Birds Atlases reveals that breeding ravens had moved approximately 120km to the southeast between the 1985 and 2005 atlas periods. Clearly by 2012 these fascinating birds had pushed another 50 to 70±km deeper into the southwest.
Finding nest sites is challenging since the adults may travel 10km to obtain food for the young. The literature indicates that dense conifer plantations can be used for nesting. The 40th Ontario Nest Record Scheme Report contains a photo of a Common Raven nest on a bridge abutment near Sudbury. In the U.S., hydro transmission towers have been used as nest sites.
Crow alarm calls can alert you to nearby ravens. Crows dive bomb ravens in a fashion similar to their attacks on hawks and owls.
As Bob Currie says in his “Birds of Hamilton”, the Common Raven is re-occupying territory abandoned 150 years ago and the return is welcomed by birders.