A Sutntnary Of·The Breeding Status of Hooded Warblers in Ontario
Total Page：16
File Type：pdf, Size：1020Kb
84 exempt from controls. Maybe it's would it be possible to send proofs time we took a look down from our to authors for checking before pub lofty perches and wised up. lication? Jon D. McCracken Ron Pittaway Vittoria, Ontario Minden, Ontario Editor's Note Corrections to Crow Note Despite rifOTOUS proofreading, errors My note on "wing-tail flicking" as a and omissions do occasionaUy slip means ofseparating crows from through in Ontario Birds. We are ravens in Volume 6(2):74-75 of happy to send proofs to authors who Ontario Birds had a typographical specifically request this when they sub error and an omission. In the first mit their manuscript, however, because sentence of the third paragraph, oftime constraints we do wt have the replace "does" with "done". Add luxury ofdoing thisfor all the words "in ravens" at the end of manuscripts. the third paragraph. In the future D. M. Fraser A Sutntnary of·the Breeding Status of Hooded Warblers in Ontario by M. E. Gartshore Introduction repeated here to provide back The purpose of the following paper ground to the current information. is to bring together information on I have focussed on records in the Hooded Warbler (Wilsonia citri June,July, and August to eliminate na) as it relates to summer occur the possibility ofconsidering rence in Ontario. In doing so I have migrants. Given that Hooded attempted to summarize important Warblers begin nesting in May and occurrences and to put them into may not leave until September, such the context ofhabitat and known a restriction may not be valid. In breeding distribution of the addition, I have not considered species. For the most part, I have records from sand spits, islands, or relied on unpublished data and known migration "hot spots" personal accounts, however, much because wandering birds may linger of the earlier information has well into the breeding season. I appeared in the literature and is have made an exception for M. E. Gartshore, R. R. #3, Dundas, Ontario L9H 5E3 ONTARIO BIRDS DECEMBER 1988 85 Rondeau Provincial Park, Kent Co., and were summarized by Baillie and PointAbino, Regional (1925), who concluded that the Municipality ofNiagara, where I species was a "rare migrant". Baillie believe the species will be did not, however, rule out the possi confirmed as breeding in the near bility of breeding because of an future. immature (skull not ossified) female collected by W. E. Saunders History atPointPelee, Essex Co., on 21 The first published Canadian August 1912 (and now deposited at record of the Hooded Warbler was the Royal Ontario Museum;]. Dick, one observed in the Hamilton area, pers. comm.). Regional Municipality ofHamilton It is ofinterest that a southwest Wentworth, by Thomas Mcllwraith erly gale produced no fewer than prior to 1860 (McIlwraith 1860). nine Hooded Warblers in Toronto, Possibly the same record was elabo Metropolitan Toronto, around rated on by McIlwraith (1894) 6 April 1947 (Bodsworth, unpubl. when he described it as a young rns.; Cunn and Crocker 1951). male (likely a female) "carried away Several lingered intoJune and at in the crowd" ofspring migran1$. least one female was seen carrying a Thereafter, records of this caterpillar by 1. Halliday on 4June species were reported sporadically in Sherwood Park (Baillie 1962). Figure 1: Summer occurrences ofHooded Warblers mapped with symbols relating to increasing levels of breeding following the criteria used by the Atlas ofthe Breeding Birds ofOntario (Cadman et al.' 1987). LAKE HURON 0~ rpJ cJf -<:7 '" 0",0 O~~"'~\O \."'~~ o '" o 0 ::J'" '" o Status Uncertain o Possible '" Probable * Confirmed ~~\~ \."'~~ VOLUME 6 NUMBER 3 86 This was the first indication that the Habitat species would breed in Ontario. Hooded Warblers occur in a variety In 1941 W. E. Saunders wrote to offorested situations in southern F. Bodsworth concerning E. M. S. Ontario. Where deciduous trees Dale's observation of a territorial dominate, territories are usually Hooded Warbler in 1940 and 1941 established in small clearings in in Fred White:s Woods (Spring forests which have been selectively water Forest) near Orwell, Elgin logged (Fig. 2). The nests are often Co., saying "looks like a steady located in regenerating shrubs in thing" (Brooman 1954). Not until the' middle of log-skidder trails. 1949 was the first nest for Canada Hooded Warblers invade areas 1-5 discovered at this site by Bodsworth years after harvesting and will (see below). remain for up to 12 years or longer Only five more nests were or until saplings exceed 5m in recorded in the province over the height and begin to shade out next 36 years, although other evi ground cover. At Springwater dence of breeding may have been Forest, where Hooded Warblers observed. The Ontario Breeding were once common, but have since Bird Atlas project provided an disappeared, the former dense important focus for further investi shrub layer consists of maple gations. Between 1985 and 1988 a saplings which are now 5-10m high. minimum of41 confirmed breed The ground is virtually devoid of ing records have been documented, cover. Where coniferous trees are most of these in Elgin and dominant, Hooded Warblers will Haldimand-Norfolk and two from occupy the dense deciduous shrub Middlesex Co. During and since the layer or regenerating hardwoods Atlas, observers may have tended to without the benefit oflogging activ establish confirmed breeding ities. In the southern United States through indirect evidence (e.g., it is standard forestry practice to observations of adults carrying burn off the low deciduous layer in food/fecal sac, fledged young) and pine stands and this can be detri this may account for the increased mental to local Hooded Warbler records in general. populations (Hamel 1980). However, most (37) of the At six Haldimand-Norfolk nest recent records are a result of the sites I measured the vegetation Natural Areas Inventory of using the quantitative methods rec Haldimand-Norfolk (NAIH-N), the ommended by James and Shugart Kent-Elgin Natural Areas Survey (K (1970). The canopy height aver ENAS) , and follow-up studies by aged 27.7m, the canopy cover was myself and the Long Point Bird 88 per cent and the shrub cover was Observatory (LPBO). Fig. 1 maps 87 per cent. Shrub stem counts summer occurrence according to ranged from 3.3 to 27.9 per m2, level ofbreeding evidence. with an average of 10.5 per m 2. ONTARIO BIRDS DECEMBER 1988 87 In my analysis, 1 broke down Distribution shrub stem density by species. A An aspect ofdistribution, which was total of66 species ofwoody plants .originally suggested to me by D. A. were involved in the sample ofsix Sutherland, is the strong correla territories. The dominant species in tion between the occurrence of the shrub layer were maple-leaved Hooded Warblers and sand plains viburnum (Viburnum acerifolium) , or sand deposits in southern red raspberry (Rubus idaeu.svar. Ontario. In Fig. 3 I have mapped strigvsus) , black raspberry (R summer records ofHooded allegheniensis) , white ash (Fraxinus Warblers and the distribution of americana), choke cherry (Prunus sand plains. The data have been virginianus) , and red maple (Acer broken down by decade. Most of rubrum). In Ontario, Hooded the records fall on large sand plains Warblers appear to require mature, and the remainder can probably be open, mesic forest with a dense accounted for by local soil condi deciduous shrub layer. Forests tions. For example, at Cayuga, which have been severely high-grad Haldimand-Norfolk, a Hooded ed and have therefore lost height of Warbler territory was located at the canopy and the ability to regener south end ofthe Oriskany sand ate woody vegetation are not usual stone formation where there is rich ly occupied. sandy loam in a landscape dominat- Figure 2: Typical habitat in the Wilson Tract, Norfolk Tp. Mun., Regional Municipality ofHaldimand-Norfolk, where several pairs ofHooded Warblers have bred 1985-88. Photo by M. E. Gartsh(J'('e. VOl.UME 6 NUMBER 3 88 ed by the Haldimand clay plain. soils in this area are alluvial in ori Hooded Warblers tend to occur gin and contain a higher propor where good forest cover remains. tion oforganic material. Aspen Eastern Elgin and western (PoPUlussp.), willow (Salixsp.), and Haldimand-Norfolk still support weedy herbaceous species tend to 16-25 per cent forest cover. invade open sites. Hooded Warblers appear to be From the available records, absent from western Kent Co. and Hooded Warblers appear to avoid southern Lambton Co. where sand an area (roughly bounded by the plains occur but the forest cover is towns ofFlesherton, Teeswater, as low as 3 per cent. However, the Seaforth, Woodstock, and Guelph) sand plain may not support the which is termed the "Ontario right kind of habitat. For instance, Island", land which first emerged at Dunnville, Haldimand-Norfolk during the retreat of the Co., the sand plain does not appear Wisconsinan ice sheet (Chapman to support Hooded Warblers, even and Putnam 1984). It is an area of though the per cent forest cover is higher elevation, usually greater high (NAIH-N data). However, the than 300m asl. Figure 3: Hooded Warbler summer occurrences mapped in relation to the dis tribution of sand plains in southern Ontario (after Chapman and Putnam 1984). Records are mapped using different symbols to indi cate decades. Where applicable, earlier records are superseded by more recent records. ... P 7t '" ~~. ~k..6'17'i' ,.... I"·'" ,. 9r ffr ·ir~. ~;~ ":~l:/F!# d ~P"'-e? -' .-:;r... ';"" ':--,,~ LAKE ONTARIO .. 11140 - 511 • l11eo - ell • 11110 - 111 * l11eo - ea E",E .end plein. o ONTARIO BIRDS DECEMBER 1988 89 Population Trends many potential woodlots possessing Without good long-term data, itis suitable breeding habitat have yet very difficult to assess population to be surveyed for this species.