HALF-CENTURY RECORD OF THE BREEDING BIRDS OF THE FORTINE AREA, MONTANA: NESTING DATA AND POPULATION STATUS WINTON WEYDEMEYER Fortine, Montana 59918 I have studied the birds of northwestern Mon- the earliest date for young may precede that tana for more than half a century (1920-73) for when eggs were actually seen. In the case during my residence as a rancher near Fortine, of multiple records, extreme dates are identi- in Lincoln County. Information on the spring fied as to year by numbers in parentheses. migration pattern there has been published Admittedly, it is not possible to afford a previously ( Weydemeyer 1973). The present true picture of the relative breeding numbers paper, listing the breeding birds of the area of most species by means of the commonly and summarizing information on more than employed adjectives used below. To present 4000 nests and about 2000 broods of young as accurate a picture as possible, descriptions out of the nest, provides data on nesting dates, relate to numbers present in preferred habi- and for some species, information on size of tats rather than in the total area. egg clutches or broods of young; the relative Gauiu immer. Common Loon. Rare, numbers de- abundance of each species, and in many cases creasing. Young about two-thirds grown seen as early definite changes in the breeding population, as 6 June ( 1942). are noted. Podiceps grisegena. Red-necked Grebe. Rare. Nest A basic list of 154 species includes 25 that with eggs, 25 May 1936. Regular at Ninepipe Refuge are regular permanent or summer residents (near Ronan, Lake County), young observed during June and July. and doubtless breed, but for which actual Podiceps auritus. Horned Grebe. Rare. Nearly- nesting data have not been obtained. In a few grown young, 29 July and 25 August 1929. cases, but only if records from the Fortine area Podicens nig~icolks. Eared Grebe. Uncommon. are also given, data from adjacent localities Nest with four eggs 15 June 1930. Variable dates shown for 19 broods of young on the water (two to within a radius of 100 miles are included. A five birds each, seven in two cases); nearly grown supplemental list names I9 additional species young as early as 12 June ( 1932), young perhaps a that breed in nearby localities and may pos- week old as late as 30 August ( 1936). Variation in sibly do so in the Fortine area. ages is shown among broods on any one lake in one The “Fortine area,” as arbitrarily designated season. Aechmophorus occidentalis. Western Grebe. Rarely herein, is that portion of Lincoln and Flathead breeds at Fortine. Third-grown young, 1 July 1923 counties lying within a 20-mile radius of my and 22 July 1922. Becoming commoner in adjacent ranch. The ranch itself, with headquarters areas to the south; one observation, 17 broods of one mile NNE of Fortine, lies at an elevation young, one-third to one-half grown, at Ninepipe Ref- uge on 11 July 1969. of about 3000 ft in the glaciated, largely tim- Podilymbus podiceps. Pied-billed Grebe. Uncom- bered Tobacco Valley, 15 miles S of the United mon. Nest with five eggs 26 May 1940. Dates on 15 States-Canadian border and 54 miles E of broods of young in the water vary greatly: range, the Montana-Idaho line. The area includes third-grown young 18 June (1933) to half-grown 6 Transition, Canadian, and Hudsonian Zone August ( 1967). Nearly grown young observed at Ninepipe Refuge as early as 11 July ( 1969). habitats. Botaurus lentiginosus. American Bittern. Uncom- As discovery of nests has to a considerable mon, decreasing. Record of 10 nests in hayfields: degree resulted from chance rather than from five eggs 4 June 1940; newly hatched young 8 July planned study, more information has been 1927; for third-grown young, dates range from 22 obtained for commoner valley birds than for July ( 1940) to 1 August ( 1944). Anus plutyrhynchos. Mallard. The commonest those that are scarcer, more secretive, or con- breeding duck. Dates for eggs range from 9 May fined to mountain habitats. Thus, the number ( 1941) to 19 June ( 1927). Dates on 201 broods in of nests or broods listed for any species is not the water show a range for young judged to be less an accurate measure of its relative abundance than one week old from 12 May (1940) to 28 July in the area. ( 1971). Of this age, 3 broods were recorded during the period of 1 to 15 May; 17 broods, 16 to 31 May; In the following summary of actual nesting 27 broods, 1 to 15 June; 13 broods, 16 to 30 June; data, no attempt has been made to establish 6 broods, 1 to 15 July; one brood 28 July. The 126 for each species a time pattern of nesting broods counted ranged from 2 to 14, the average being 7. progress. Thus, egg dates are not estimated Anus UCU~U. Pintail. Breeds rarely at Fortine, from records of young in nests; in some cases though commonly southward. Records of seven 12811 The Condor 77:281-287, 1975 282 WINTON WEYDEMEYER broods in the water indicate a range in hatching dates Bucephala islandica. Barrows’ Goldeneye. Com- from late May to mid-June. One brood nearly grown, mon. Data on 46 broods indicate a shorter nesting 12 July 1931. period than that of B. clungula. Young left a nest 18 Anas creccu. Green-winged Teal. Formerly a com- June 1935. Dates for young less than one week old mon breeder at Fortine but numbers show a drastic in the water range from 29 May (1934) to 15 July reduction in recent years. Dates on eggs range from ( 1972). Eight broods on one lake in 1938 were nearly 11 May (1928) to 23 June (1923). Dates on 43 uniform in size. The 44 broods counted ranged from broods in the water show a wide range: young judged 4 to 11 in number, with an average of 8. to be less than one week old, 13 May (1946) to 15 BucephaZa aZbeoZa. Bufflehead. Fairly common, August ( 1928). Of this age, three broods were seen increasing. Dates for young judged to be less than during the period of 13 to 31 May; seven broods, 1 one week old range from 11 June (1971) to 5 July to 15 June; five broods, 16 to 30 June; three broods, ( 1970); nearly grown young have been seen as early 1 to 15 Tulv: three broods. 12 to 15 August. The 31 as 12 Tulv 1970 ). Brood numbers ranged from 1 ” ,, C broods counted ranged from 4 to 15, the average to 12, with an average for 32 broods of 5.- being 8. Histrionicus histrionicus. Harlequin Duck. Rare. Anas discors. Blue-winged Teal. Uncommon. Young in the water observed during July and August. Dates for eggs range from 13 June (1935) to 31 Oxyura jamaicensis. Ruddy Duck. Fairly common, July ( 1961). Data on young in the water indicate Dates for eggs range from 12 June (1932 and 1938) that usual hatching dates range through June. Nearly to 1 July (1923); as many as 19 eggs found in one grown young observed by 6 August ( 1967). nest. Broods in the water averaged eight in number. Anus cyanoptera. Cinnamon Teal. Rare, decreas- Data on 39 broods show a wide range of dates: young ing. Have a few July dates for small young. one-third grown as early as 14 June ( 1931), and Anus americana. American Wigeon. Common, in- young perhaps 10 days old as late as 30 August creasing. Dates on 19 broods in the water (3 to 15 (1931). in number, average 7) indicate a rather uniform Lophodytes cucullatus. Hooded Merganser. Breeds hatching period during the first 20 days of June. rarely. Five records for young in the water indicate Anus clypeata. Northern Shoveler. Rare or casual hatching dates in early June. Five young about two- breeder. Thirteen young appearing to be less than thirds grown with an adult female of this species seen one week old seen 31 May 1971. on 12 July 1970 appeared to be Hooded Merganser- Aythya americana. Redhead. Increasing; began Bufflehead hybrids. nesting at Fortine about 1932, has become fairly Mergus merganser. Common Merganser. Uncom- common. Eggs, 12 June 1932. Dates for 27 broods mon. Data on seven broods (8 to 12 young) indicate in the water (5 to 10 in number, average 7) show an early nesting season: young one-third grown by a range for young judged to be less than one week 14 June; fully grown young by 19 July ( 1931). old from 12 June (1938) to 28 July (1971). Accipiter gentilis. Goshawk. Rare, decreasing. Im- Aythyu collaris. Ring-necked Duck. Uncommon, mature young on the wing observed 8 and 25 August increasing. Not regularly present in summer until re- 1922 and 15 August 1942. cent years. First young seen in 1970, three broods Accipiter striatus. Sharp-shinned Hawk. Decreas- in 1971, two in 1972, five in 1973. These indicated ing to rare in recent years. Young left a nest by mid- a range in hatching dates from about 20 June to 15 June. Fully grown flying young seen 2 August ( 1931 July. Broods 2 to 12 in number, average 6. and 1932 ) . Aythya valisineria. Canvasback. Breeds rarely. Accipiter cooperii. Coopers’ Hawk. Decreasing to Three broods, l-2 weeks old, seen 22 July 1973. uncommon in recent years. Flying young seen 2 Aythya uffinis. Lesser Scaup. Only one Fortine August 1924. area breeding record: 11 young perhaps two weeks Buteo jamaicensis. Red-tailed Hawk. Decreasing to old, with two adult females and two adult males, 15 uncommon in recent years.