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Roosting habits and Post-breeding dispersal of juvenile Great Egrets in Ontario.

www.ec.gc.ca. Roosting habits and Post-breeding dispersal of juvenile Great Egrets in Ontario. D.V. Chip Weseloh & Dave Moore Canadian Wildlife Service - Ontario. With field assistance by Linda McLaren, Tyler Hoar and Dave Andrews. Harbor Herons and Waterbirds of Greater

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Roosting habits and Post-breeding dispersal of juvenile Great Egrets in Ontario.

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  1. www.ec.gc.ca Roosting habits and Post-breeding dispersal of juvenile Great Egrets in Ontario. D.V. Chip Weseloh & Dave Moore Canadian Wildlife Service - Ontario With field assistance by Linda McLaren, Tyler Hoar and Dave Andrews Harbor Herons and Waterbirds of Greater NY/NJ Harbor Working Group 12-13 January 2011 Staten Island, NY

  2. Objectives for 2010 • Confirm seasonal use pattern at major roost site. • Locate other roost sites, track numbers and usage. • Mark YOY egrets with highly visible wing-tags • Make greater efforts at re-sighting tagged egrets SUMMARY • Not used in spring, bimodal autumn peak #s • 30 roost sites;NN= 8, 24 km; Roost size = 2-400+ • 118 egrets tagged at 3 sites • 39 individuals reobs., Egrets go to S. Ontario, Michigan, Ohio and NY- Few birds went north.

  3. Locations of colonies & nest numbers – 2000s Dickerson Island Bergin Island High Bluff Island Middle Island Barrier Island Nottawasaga Island Lake Huron Lake Ontario Luther Marsh Chantry Island Toronto Harbour Motor Island Number Number of East Sister Island of Nests Lake Erie Colonies (maximum) Decade Middle Sister Island 1950s 1 1 1960s 2 10 1970s 4 63 1980s 4 108+ 1990s 6 178 2000s 359+ 11

  4. Use of Luther Marsh roost site, by week, 2008-09 300 2008 2010 2009 2009 2008 200 Opening day - duck hunting: 27 Sep. 2008 26 Sep. 2009 No. Great Egrets at Roost (mean/week) 100 no egrets present 0 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 Apr May Jun Jul Aug Sep Oct Date

  5. 300 2008 2010 2009 2009 2008 2010 200 No. Great Egrets at Roost (mean/week) 100 0 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 Apr May Jun Jul Aug Sep Oct Use of Luther Marsh roost site, by week, 2008-10 Opening day - duck hunting: 27 Sep. 2008 26 Sep. 2009 25 Sep. 2010 no egrets present Date

  6. Locations of Great Egret Roosts in the Lower Great Lakes Region = Confirmed Roosts = Unconfirmed Roosts = >100 Birds 27. 28. 29. 26. 30.

  7. GREG roosts – nearest neighbour distances 15 mean = 84.6±47.2 km (N = 24) Median = 24 km Mode = 8 km range = 1 – 160 km 10 No. Colonies 5 0 1-20 km 21-40 km 41-60 km 61-80 km 81-100 km >100 km Nearest Neighbour Distance

  8. Occupancy of GREG roosts, 2010 20 20 probable confirmed 15 15 Number of confirmed & probable roost sites occupied 10 10 5 5 0 0 1 1 2 2 3 3 4 4 1 1 2 2 3 3 4 4 1 1 2 2 3 3 4 4 1 1 2 2 3 3 4 4 1 1 2 2 3 3 4 4 1 1 Jun. Jun. Jul. Jul. Aug. Aug. Sep. Sep. Oct. Oct. Nov. Nov. Week

  9. 4 Metcalfe the Coves 3 2 1 0 1-Aug 8-Aug 25-Jul 3-Oct 5-Sep 15-Aug 22-Aug 29-Aug 10-Oct 12-Sep 19-Sep 26-Sep Occupancy of small roosts, 2010 No. of GREGs at roost Date

  10. Applying wing-tags

  11. Applying wing-tags

  12. Tagged egrets in the field

  13. Tagged egrets in the field

  14. Re-sightings of wing-tagged GREGs All re-sightings, 2010 ON ON Nottawasaga I. Nottawasaga I. 2 Chantry I. Chantry I. 5 8 5 6 2 3 NY NY 2 MI MI Middle Sister I. Middle Sister I. PE PE OH OH

  15. www.ec.gc.ca

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