September. 1920] 



The Canadian Field-Natukalist 



109 



NOTES ON THE FAUNA AND FLORA OF EAST AND MIDDLE SISTER AND 

 NORTH HARBOR ISLANDS, LAKE ERIE. 



By E. W. Calvert, Arner, Ont. 



The following observations were made during a 

 two days' trip to the islands, which are situated a 

 few miles west of Pelee island in western Lake 

 Erie. All have rocky shores with much shingle or 

 coarse gravel and have a number of bays and 

 shoals. Owing to a severe gale most of the time 

 was spent on North Harbor island which contains 

 but slightly over an acre in its area. The island is 

 narrow and a ridge follows the centre. The fol- 

 lowing trees were found, being arranged in order 

 of their abundance: — White Elm, Hackberry, Ken- 

 tucky Ccffee Tree, Sugar Maple, Chokecherry, 

 Cottonwood, Staghorn Sumach and a shrubby 

 willow. Along shore were observed several large 

 stumps of the Red Cedar no doubt flourishing many 

 years ago. Of the shrubs and vines the common 

 elder (Sambucus Canadensis) is represented and 

 Virginia Creeper, Climbing Bittersweet (Celasirus), 

 Wild Grape and Poisin Ivy abound. No attempt 

 has been made to tabulate the herbaceous plants as 

 a number were not familiar to the writer. 



The item of greatest biological interest however 

 is a large colony of the Common Tern (Sterna 

 hirundo) the estimated number of birds being 2,000 

 to 2,500. Some 800 occupied nests were counted 

 over half of which contained three eggs, about one 

 quarter containing two, a few with four and the 

 remainder with one. The nests were situated on 

 the shingle a few feet above the water. Some were 

 somewhat concealed by foliage and driftwood, 

 others were in plain view but blended rather well 

 with the shingle, thus making it necessary to pick 

 one's steps. Most of the nests were composed of 

 broken reeds and bits of driftwood but in some 

 green leaves were employed, while in still others 

 there was merely a hollow in the shingle ; these 

 were exceptional however. The nests were often 

 as close as two feet to one another and were most 

 numerous in the troughs of shingle formed by the 

 action of the waves. The ground color of the eggs 

 is a pale greenish or yellowish buff with variable 

 dark spots sometimes forming a ring at the larger 

 end. The eggs vary greatly in color, even in the 

 same nest very light and very dark examples being 

 frequent. During our whole stay the birds kept 

 up an incessant noise and seemed to treat our pres- 

 ence with great disapproval. While at this island 

 only one bird had hatched this being found just 

 previous to our departure on the 21st of June. 



The bird population of the island other than 

 tern was scant consisting of a Red-eyed Vireo and 



a Song sparrow, a visiting (?) pair of Kingbirds, 

 as well as several Bronzed Crackles and a Crow, 

 present no doubt for nest robbing as the terns made 

 a great noise during their presence. Several Her- 

 ring Gulls and a Bank Swallow were also noted 

 flying past. 



The next island visited was East Sister and con- 

 tains thirty or more acres, about ten of which is 

 cleared and is planted to peach trees and garden 

 crops chiefly. As might be surmised, owing to its 

 much larger size all branches of the fauna and 

 flora were represented by a larger number of spe- 

 cies than was the island previously visited. In ad- 

 dition to the trees enumerated as found on North 

 Harbor the following were found on East Sister: — 

 Basswood, Shellbark Hickory, White Ash, Silver 

 Mciple, Aspen, Sycamore, Red Elm and a species 

 of Dogwood. The most abundant bird on this 

 island was the Bronzed Grackle but the House 

 sparrow, Kingbird and Red-winged Blackbird 

 were also well represented. The followmg were 

 also noted in small numbers: — Crow, Red-eyed 

 Vireo, Wood Pewee, Cedar Waxwing, Cowbird, 

 Robin, Killdeer and Turkey Vulture. According 

 to report the Cottontail is found here but no other 

 mammal is known, but no doubt others occur. 



The last island visited is somewhat isolated, be- 

 ing about ten miles from the others and about 

 twelve from the mamland. It contains some eleven 

 acres, all of which are densely wooded, and has 

 high rocky banks. On the side facing east is a 

 promontory of rock and on the opposite side great 

 windrows of gravel where Common Terns nest m 

 great numbers. The tern population of this island 

 was estimated at some 8,000 and the occupied nests 

 at 1,500 to 2,000. Apparently over half of these 

 had been robbed earlier in the season as the unoc- 

 cupied nests were quite as numerous as the occu- 

 pied ones. On the day the island was visited (June 

 22nd) about twenty per cent, of the birds were 

 hatched but probably these did not start to hatch 

 before the 20th. 



The trees found on this island were almost identi- 

 cal in species to those found on North Harbor, the 

 Red Cedar being alive in this case and the Sumach 

 absent. Other than the terns, the following birds 

 were noted: — Indigo Bunting, Kingbird, Red-eyed 

 Vireo, Carolina Wren and a flock of about 500 

 Herring Gulls which left the bar on our approach. 

 A visit to the island on May 30 revealed the pres- 



