This morning, between 0625 and 0725, I observed 23 Great Egrets fly into Cranberry Marsh from the east, part of the above Conservation Area. The egrets settled into the marsh and began foraging immediately.
Earlier, at 0612, I had confirmed that the egrets were roosting in trees on the west bank of Lynde Creek, due east of the marsh and opposite the south end of the largest island in the creek. Of the 23 egrets in this group, four of them carried green wing-tags. I was able to read the numbers and letter on all four tagged birds; they had all been banded and tagged on Nottawasaga Island, near Collingwood, on 30 June 2015. And, thus, were about 3 months old and had been flying for less than 2 months. I have been tracking the roosting habits of the egrets that forage in Cranberry Marsh since 2011; the egrets are very consistent in their behaviour. In the late afternoon/early evening, as dusk approaches, they will fly off from Cranberry in an ENE direction toward Lynde Creek (a distance of less than half a km) where they will immediately settle either in the trees along the shoreline or, if the water is shallow enough, in the water/mudflats at the south end of the island. Their evening departure from Cranberry is a slow process and may take 30 minutes or more for all the birds to leave. In the morning, about 10-15 minutes before official sunrise, they fly out from their roost...usually over a span of only about five minutes. Most of them fly directly to Cranberry, arriving from the east and settling in the south or west side of the marsh to forage. A few birds sometimes fly north and feed near the boardwalk...but never very many and usually none at all. Though I have never spent an entire day (sunrise to sunset) at Cranberry to see if the egrets stay there all day, I receive reports (from Ontbirders) of them there from throughout the day. The Cranberry Marsh - Lynde Creek foraging - roosting "system" seems very closed. I have never seen birds arrive at Cranberry, in the morning, from any direction other than the east nor have I seen any of the egrets foraging at Cranberry depart in any direction, at dusk, other than ENE towards the creek. This is very interesting given that many of the lakeshore marshes between Pickering and Oshawa each appear to harbour roosts of egrets; egrets also roost at the mouth of the Rouge River, at Ajax Rotary Park and at Oshawa Second Marsh. I do not know if the foraging habits of the egrets roosting in those marshes are as confined as those at Lynde Shores. The predictable nature of the (tagged) egrets at Cranberry makes it possible to identify how long given individuals may stay in a specific area before they carry on with their migration. Herons (and egrets) notably undergo a period of dispersal after leaving their breeding colony, or the colony where they were born, before they begin their actual migration. In the past, tagged birds have stayed for anywhere from a few days to 3-4 weeks at Cranberry Marsh. Two of the tagged egrets that are presently at Cranberry have been there since at least 2 August. If any Ontbirders have not yet had a chance to view a tagged egret, I suggest you head down there to take a look; please let me know what you see for egrets. For Ontbirders who regularly go to Cranberry Marsh, please keep sending me the number of egrets observed there as well as the number-letter combinations that are on any of the tagged egrets (and the colour of the tag) so we can continue to see how long these four birds stay at Cranberry-Lynde Shores. Many thanks, Chip Directions to the west observation platform of Cranberry Marsh): From Hwy 401 east of Toronto, take the Salem St. Exit, go south to Victoria St. (aka Bayley St.), go left (east) for about 1 km, turn right on Halls Road, continue less than a km until you see signs for Cranberry Marsh on your left, park your car along the road and follow the path to the observation platform. If you get to the signs about the "Hawk Watch" along Halls Road, you have gone too far. I look forward to your reports...please send privately. J _______________________________________________ ONTBIRDS is presented by the Ontario Field Ornithologists - the provincial birding organization. Send bird reports to [email protected] For information about ONTBIRDS including how to unsubscribe visit http://www.ofo.ca/site/page/view/information.ontbirdssetup Posting guidelines can be found at http://www.ofo.ca/site/page/view/information.ontbirdsguide
