32 Recent Nestings of Red-necked Grebe on Lake Ontario

Robert Z. Dobos and Gavin Edmondstone

Introduction 1944 (Speirs et al. 1944). The 1943 The breeding range of the Red­ nests were either built in sub­ necked Grebe (Podiceps grisegena) merged crotches of small willows in North America extends from along the shoreline, or as floating Alaska through western and cen­ mats of vegetation. The latter nest tral-southern Canada and north­ type is more typical of this species, western United States east to as it usually nests in freshwater northeastern Ontario and west-cen­ marshes (Harrison 1984). A nest tral Quebec (Godfrey 1986, was also found farther east along Lapointe 1996). Within Ontario, it is the Lake at Lorne Park (present considered a rare breeder restricted day Mississauga), Peel, in 1946 to specific traditional areas,gener­ (Gunn 1951). These nestings were ally in the northwestern and south­ not entirely surprising, since it was central parts of the province known by as early as the 1930s that (Armstrong 1987). In southern Red-necked Grebes regularly spent Ontario, it is known to have bred the summer along the Halton and formerly at isolated locations in Peel lakeshores in numbers up to Wellington and Simcoe Counties, about 100 birds (Gunn 1951). This Peel and Halton Regional summering occurrence has contin­ Municipalities and Manitoulin ued up to the present, although in District (Peck and James 1983). smaller numbers. Over the past However, there has been a reduc­ decade, a summering flock of 20-40 tion in the distribution and number birds typically has been present of breeding pairs in Ontario over along the Burlington lakeshore the past several decades, and as a each year (pers. obs.). result, this species has been identi­ The purpose of this article is to fied as being of conservation con­ document recent nestings of this cern (Austen et al. 1994). species along the western shoreline The historical nestings of Red­ of Lake Ontario within Halton necked Grebe on Lake Ontario at Regional Municipality. Burlington, Halton, are of interest, since this is the most southerly nest­ Appleby Creek Nesting ing location for this species in On 25 July 1994, Dobos found a Canada. It was first found nesting in pair of Red-necked Grebes with a 1943, with up to seven nests pre­ nest along the Lake Ontario shore­ sent, and two nests subsequently in line at the mouth ofAppleby Creek

ONTARIO BIRDS APRIL 1998 33

in the City of Burlington, Halton. small rope to the breakwater, and The shoreline in this vicinity is appeared to have been intentional­ heavily urbanized, with private res­ ly placed at this location. The nest idences occupying the lakeshore. was a low mound consisting of large The shoreline itself has been twigs, branches, aquatic vegetation altered drastically with concrete, and algae, about two feet across. boulder or steel sheetpile revet­ The nest had a slight depression in ments for erosion protection along the centre within which could be most of its length. Essentially no seen a minimum of four large, tan­ natural shoreline remains in this coloured eggs. After a short time, area. one of the grebes swam up to and At this location, two adult hopped onto the board, then settled grebes were first sighted very close onto the nest to incubate the eggs. to shore. It was then noticed that a This nest was visited again on floating wooden board about one 27 July 1994 by Dobos, at which square metre in size, located time photographs were taken of an between the shore and an "L"­ adult Red-necked Grebe incubat­ shaped concrete breakwall which ing this nest (Figure 1). The site was juts into the lake, supported an next visited on 11 August, when two obvious nest structure made from adult grebes were seen swimming vegetation. The board was tied by a nearby, but the nest apparently had

Figure 1: Red-necked Grebe incubating nest at mouth of Appleby Creek, 27 July 1994. Photo by Robert Z. Dobos. VOLUME 16 NUMBER 1 34 been abandoned. Upon closer On 1 July 1997, the birds were inspection, there were no signs of observed piling vegetation onto the any egg shells, and the nest mound tire in the northeast corner of the was reduced and appeared to be harbour. There was a sailboat unmaintained. There were no grebe moored at the tire at the time. On 8 chicks evident with the adults, and July, one of the birds was observed the birds did not display any terri­ incubating. Four eggs were torial behaviour. It was concluded observed from shore on 13 July. that the nesting had not been suc­ Both birds took turns incubating. cessful. Mallards (Anas platyrhynchos) and The next year, this site was vis­ Canada Geese (Branta canadensis) ited on 7 and 26 June 1995 by that came too close to the nest were Dobos. Two adult· Red-necked subject to attack from below. The Grebes were present on both occa­ incubating birds seemed little dis­ sions, along with the floating board, turbed by the boat activity in the but no sign of nesting activity was harbour. The approach of a jet ski evident. A final visit on 13 July pro­ would sometimes cause the bird to duced only a single grebe, and rio slip off the nest briefly. nesting activity. The site was On 5 August 1997, one chick checked the following year on 4 was seen at the nest. On the next July 1996, and eight adult grebes day, the chick was swimming. Often, were present offshore nearby, but it was offered fish that were too big the floating board was no longer for it to swallow. Two chicks were present and no nesting activity was observed on 7 August. On the night detected. of 8 August, a visiting sailboat ran over the nest tire in an attempt to Bronte Harbour Nesting moor at it. Bystanders informed the On 30 June 1997, Edmondstone boaters of the nest and the boaters observed two adult Red-necked left. There was no sign of the other Grebes vocalizing in Bronte Outer two eggs when the nest was Harbour on the Lake Ontario checked by Edmondstone using a shoreline near the mouth of Bronte boat on 11 August. Once mobile, Creek in the Town of Oakville, the grebe fami!y seemed quite Halton. This harbour is protected unperturbed by any human activity. from the lake by a pair of stone These birds developed a following breakwalls. In the 1997 boating sea­ in the local community, with as son, the outer harbour had not been many as 20 people at a time gath­ developed, with only eight floating ered to watch them. tires being available for visiting There was an abundance of boats to moor at and no permanent small fish for the growing birds. dock space available. Rivalry for feeding was not

ONTARIO BIRDS APRIL 1998 35 observed; on at least one occasion, a Additional Breeding Attempts chick declined a fish offered by a A pair of Red-necked Grebes parent. On 16 August 1997, the two engaged in nest building activity chicks were photographed at the was observed on 8 June 1991 by nest (Figure 2), one of the last times Kevin A. McLaughlin (pers. comm.) the nest was used. On 29 August, on the lakeshore off Shoreacres the chicks were observed catching (a.k.a. McNichol Park) in insects. By early September 1997, Burlington. The birds Were gather­ the chicks were frequently left ing algae and bringing it onto an alone by their parents. The last isolated part of a low concrete wall sighting of all four birds was on 7 which was partly submerged and October. The remaining chick was extended perpendicular from the last seen on 26 October. The adults shoreline. One of the birds also was remained until the end of observed sitting on the concrete November 1997, even chasing off a wall at times. On the next visit to Horned Grebe (Podiceps auritus) the site on 20 June (and subsequent on 26 November. visits over the next month), there

Figure 2: Red-necked Grebe with two chicks on a floating tire nest in Bronte Harbour, 16 August 1997. Photo by Gavin Edmondstone.

VOLUME 16 NUMBER 1 36 were no signs of a possible nest. Red-necked Grebes at the west end During a visit to the same of Lake Ontario, it is not surprising Shoreacres site on 29 May 1994 by that nesting attempts have been K.A. McLaughlin, Paul Pratt and documented occasionally. The high­ others, a pair of Red-necked ly altered and developed nature of Grebes was briefly observed copu­ the shoreline in this area provides lating (K.A. McLaughlin, pers. extremely limited nesting habitat comm.). This site is about 1.2 km for this species. Human activity, pri­ from the location of the nest found marily from recreational boaters two months after this event (as and jet skis, urban wildlife preda­ described above), but it is unknown tors, and wave disturbance during whether the same birds were storm events would all provide haz­ involved. ards to successful breeding and On 4 July 1997, Dobos fledging of young. The recent suc­ observed two Red-necked Grebes cessful nesting at Bronte Harbour in nest building activity on the occurred in an area that provided lakeshore off Sioux Lookout Park some shelter from some of these in Burlington. These birds were div­ factors, since it was located within ing to retrieve vegetation, then car­ the outer harbour area which is rying algae and small branches to a protected from the waves of the site on the shore behind a short open lake by an exterior rock concrete pier on the eastside of the breakwall. mouth of Roseland Creek. The Following the discovery of the actual site where the nest was being first nests at Burlington in 1943, constructed could not be seen and local members of the Hamilton was unapproachable since it was on Nature Club (HNC) started a pro­ private property. On subsequent gram of providing artificial nesting visits over the following weeks, platforms for these birds. The two there were no signs of these birds nests found at Burlington in 1944 and no indication of successful nest­ were built on floating wooden plat­ ing. forms specifically put out for the Additional breeding behav­ birds (Speirs et al.1944). These plat­ iours have been observed amongst forms were placed behind a break­ the summering grebes at wall in Burlington Harbour (the Burlington on many occasions. current site of Spencer Smith Park) Vocalizations of breeding calls have which provided some shelter simi­ been heard regularly throughout lar to the current Bronte Harbour the summer months (pers. obs.). situation. The HNC continued to put out these nesting platforms Discussion until at least the early 1950s, as well Given the numbers of summering as at sites in Dundas Marsh,

ONTARIO BIRDS APRIL 1998 37

Hamilton-Wentworth, and at the Austen, M.J.W., M.D. Cadman and R.D. west end of Hamilton Harbour, James. 1994. Ontario Birds at Risk: Status and Conservation Needs. Federation of Hamilton-Wentworth (Benner Ontario Naturalists, Don Mills, Ontario. 1952). However, no indication Benner, W.E. 1952. Outing to bring in the could be found that these structures grebe floats. Wood Duck 6(3): 8. continued to be used by nesting Godfrey, W.E. 1986. The Birds of Canada. Revised Edition. National Museums of grebes during the 1950s. Canada, Ottawa. In light of its status as a rare Gunn, W.W.H. 1951. The changing status of Ontario breeder, and given the the Red-necked Grebe in southern recent nestings of Red-necked Ontario. Canadian Field-Naturalist 65: 143-145. Grebes on artificial structures, as Harrison, C. 1984. A Field Guide to the well as the continuing presence of Nests, Eggs and Nestlings of North summering grebes on Lake American Birds. Collins, Toronto. Ontario, it may be a worthwhile Lapointe, J. 1996. Red-necked Grebe (Podiceps grisegena). Pp. 218-219 in The activity for wildlife agencies or local Breeding Birds of Quebec: Atlas of the naturalist groups to undertake an Breeding Birds of Southern Quebec (I artificial nesting structure program Gauthier and Y. Aubry, editors). for this species at appropriate loca­ Association quebecoise des groupes d'or­ nithologues, Province of Quebec Society tions. for the Protection of Birds, Canadian Wildlife Service, Environment Canada, Acknowledgements Quebec Region, Montreal. The authors wish to thank: Kevin Peck, G.K. and R.D. James. 1983. Breeding Birds of Ontario: Nidiology and McLaughlin for providing details of Distribution. Volume 1: Nonpasserines. his observations; Ron Pittaway and Life Sciences Miscellaneous PUblications, Ron Tozer for assistance in obtain­ Royal Ontario Museum, Toronto. ing references for this article; and Speirs, J.M., G.W. North and J.A. Crosby. 1944. Holboell's Grebe nesting in southern Bob Curry for information on his­ Ontario. Wilson Bulletin 56(4): 206-208. torical nestings.

Literature Cited Armstrong, E.R. 1987. Red-necked Grebe (Podiceps grisegena). Pp. 42-43 in Atlas of the Breeding Birds of Ontario (M.D. Cadman, P.EI Eagles and EM. Helleiner, compilers). University of Waterloo Press, Waterloo, Ontario.

Robert Z. Dobos, 1156 5th Concession Road West, R.R. 2, Waterdown, Ontario LOR 2H2 Gavin Edmondstone, 502 - 2511 Lakeshore Road West, Oakville, Ontario L6L 6L9

VOLUME 16 NUMBER 1