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

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 1.Not used in spring, bimodal autumn peak #s 2.30 roost sites;NN= 8, 24 km; Roost size = 2-400+ 3.118 egrets tagged at 3 sites 4.39 individuals reobs., Egrets go to S. Ontario, Michigan, Ohio and NY- Few birds went north.

3. Lake Huron Lake Erie Lake Ontario Chantry Island Nottawasaga Island Middle Sister Island East Sister Island Middle Island Toronto Harbour High Bluff Island Locations of colonies & nest numbers – 2000s Dickerson Island Bergin Island Motor Island Decade Number of Colonies Number of Nests (maximum) 1950s11 1960s210 1970s463 1980s4108+ 1990s6178 2000s 11 359+ Barrier Island Luther Marsh

4. Use of Luther Marsh roost site, by week, 2008-09 Opening day - duck hunting: 27 Sep. 2008 26 Sep. 2009 0 100 200 300 1234123412341234123412341 AprMayJunJulAugSepOct 2010 2009 2008 2009 No. Great Egrets at Roost (mean/week) Date no egrets present

5. Use of Luther Marsh roost site, by week, 2008-10 Date Opening day - duck hunting: 27 Sep. 2008 26 Sep. 2009 25 Sep. 2010 no egrets present

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

7. GREG roosts – nearest neighbour distances 0 5 10 15 1-20 km21-40 km41-60 km61-80 km81-100 km>100 km Nearest Neighbour Distance No. Colonies mean = 84.6±47.2 km (N = 24) Median = 24 km Mode = 8 km range = 1 – 160 km

8. Week Number of confirmed & probable roost sites occupied Occupancy of GREG roosts, 2010 0 5 10 15 20 123412341234123412341 Jun.Jul.Aug.Sep.Oct.Nov. 0 5 10 15 20 123412341234123412341 Jun.Jul.Aug.Sep.Oct.Nov. probable confirmed

10. Occupancy of small roosts, 2010 Date No. of GREGs at roost

11. Applying wing-tags

13. Tagged egrets in the field

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

16. www.ec.gc.ca