Raptor Research A Quarterly Publication of The Raptor Research Foundation, Inc, Volume 18, Number 3, Fall 1984 (ISSN 0099-9059) Contents The Peregrine Falcon (Fake peregrmus macropus} Swamson in Southeastern Queensland, G v. Cacchura 81 Spring and Fall Migrations of Peregrine Falcons in Central Alberta, 1 979-1983, with Comparison to 1969-1978. Diet Ddtkcr * 92 Winter Habitat Se action of Diurnal Raptors in Central Utah, David L_ Fiat her. Kevin I_ Ellis and Kohcrt J . 98 Do Northern Harriers Lay Replacement Clutches? Robert Edward Slmmom 103 Unusual Predatory and Caching Behavior of American Kestrels in Central MISSOURI. Brian Tnlznd 107 Sho rt Co m m u n ic ati ons 1981 - An Emraordinary Year for Golden E-nj^le "Triplets” in ihe Central Rocky Mountain*. M. AJan | rn kms, and Ronald A- Joseph Ill Fend Piracy Between Eurnpean Kestrel and Short-eared Owl. Erkkl Eorpimaii 1 13 All Unusual OlrtEmiiun of 'Homing' to Prey By a Migrating Immature Peregrine Falcon. CarT Salma 113 News and Reviews 91, 97, 10? + 1 15, 1 16 The Raptor Research Foundation y Inc- Provo, Utah THE RAPTOR RESEARCH FOUNDATION, INC. (Founded 1966) OFFICERS PRESIDENT: Jeffrey L. Lincer, Office of the Scientific Advisor, 2086 Main Street, Sarasota, Florida 33577 VICE-PRESIDENT : Richard Clark, York College of Pennsylvania, Country Club Road, York, Pennsylvania 1 7405 SECRETARY: Ed Henckel, RD 1, Box 1380, Mt. Bethel, Pennsylvania 18343 TREASURER: Gary E. Duke, Department of Veterinary Biology, 295K Animal Science/ Veterinary Medicine Build- ing, University of Minnesota, St. Paul, Minnesota 55208 BOARD OF DIRECTORS EASTERN DIRECTOR: James A. Mosher, Appalachian Environmental Laboratory, University of Maryland, Frostburg State College Campus, Gunter Hall, Frostburg, Maryland 21532 CENTRAL DIRECTOR: Patrick T. Redig, Department of Veterinary Biology, 295 Animal Science/Veterinary Medicine Building, University of Minnesota, St. Paul, Minnesota 55108 MOUNTAIN & PACIFIC DIRECTOR: A1 Harmata, Department of Biology, Montana State University, Bozeman, Montana 59717 EAST CANADA DIRECTOR: David M. Bird, Macdonald Raptor Research Centre, Macdonald Campus of McGill University, 21,111 Lakeshore Road, Ste. Anne de Bellevue, Quebec H9X ICO WEST CANADA DIRECTOR: R. Wayne Nelson, 4218 -63rd Street, Camrose, Alberta T4V 2W2 INTERNATIONAL DIRECTOR: Martin BOttcher, Postfach 2164, Steinfelder Strass 11, 5372 SCHLEIDEN, Federal Republic of Germany, GERMANY DIRECTOR AT LARGE # 1 : Michael Collopy, University of Florida, School of Forest Resources and Conservation, 118 Newins-Ziegler Hall, Gainesville, Florida 32601 DIRECTOR AT LARGE #2: Tom Dunstan, Department of Biological Sciences, Western Illinois University, Macomb, Illionis 61455 DIRECTOR AT LARGE #3: Mark R. 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Other communications may be routed through the appropriate Officer or Board member. All inquiries concerning the journal should be addressed to Clayton M. White, Editor, Raptor Research, Department of Zoology, 161 WIDB, Brigham Young University, Provo, Utah 84602, U.S. A. ******************* Published quarterly by The Raptor Research Foundation, Inc. Business Office: Gary E. Duke, Treasurer, Depart- ment of Veterinary Biology, 295K Animal Science/Veterinary Medicine Building, University of Minnesota, St. Paul, Minnesota 55108, U.S. A. Printed by Press Publishing Limited, Provo, Utah 84602. Second-class postage paid at Provo, Utah. Printed in U.S.A. RAPTOR RESEARCH A QUARTERLY PUBLICATON OF THE RAPTOR RESEARCH FOUNDATION, INC. VOL. 18 Fall 1984 No. 3 THE PEREGRINE FALCON (Falco peregrinus macropus) Swainson IN SOUTHEASTERN QUEENSLAND G. V. CZECHURA Abstract - Most studies of Peregrine Falcon ( Falco peregrinus) biology have been conducted in Europe and North America (Hickey and Anderson 1969; Ratcliffe 1980; Cade 1982). Information concerning southern hemisphere Peregrines is restricted to the studies of Clunie (1972, 1976) on Fiji, reviews by Cade (1969), Brown (1970) and Steyn (1982) of African populations, while Chaffer (1944), Jones and Bren (1978), Norris et al. (1977), Olsen and Olsen (1979), Olsen et al. (1979), Olsen (1982), Pruett-Jones et al. (1981 a, b), Walsh (1978) and White et al. (1981) provide important contributions for Australia. Declines in some nothern hemisphere popula- tions due to the effects of pesticides (Hickey 1969; Bijleveld 1974; Newton 1979; Ratcliffe 1980; Cade 1982) have served to focus considerable attention on the distribution and dynamics of regional Pereg- rine Falcon (Falco peregrinus) populations. Concern has been expressed about the potential affects of pesticides on populations of this falcon within Au- stralia (Olsen and Olsen 1979, 1981; Pruett-Jones et al. 1981b). Existing studies on the status of the peregrine within Australia have been conducted in the southeastern corner of the continent (Olsen and Olsen in press) and little is known of the status of northern and western populations. The following reviews the present state of knowledge of the peregrine in southeast Queensland. A more detailed, long-term study is underway. Materials and Methods Information for this review was obtained from Queensland Museum records, literature, and previously unpublished obser- vatios of both myself (1968 to present) and others. Geographic units referred to as southeastern Queensland and Moreton and Wide Bay — Burnett region follow Roberts (1979) and Mather (1976), respectively. Note that a bias toward the Moreton region exists - reflecting distribution of observers. Sufficient information is available for the presentation of a broad outline of distribution, breeding, hunting and conservation problems of peregrines over southeastern Queensland as a whole. Vegetation terminology follows Groves (1981). Distribution Peregrine Falcons have been recorded over much of southeastern Queensland (Fig. 1 ; Table 1). In addition, they have been recorded in the im- mediate vicinity of the regional boundary (Broad- bent 1889; Barnard and Barnard 1925; Longmore 1978; Passmore 1982). Vegetation type appears to exert little or no influence on the overall distribu- tion here, as closed-forests, open-forests, wood- lands, wetlands and agricultural areas are all fre- quented by falcons. For example, Dwyer et al. (1979) recorded peregrines from 8 of 12 habitat types found across Cooloola. The vegetation types represented here included vine forest, various forms of open forest and woodland as well as heath, herb and sedgeland. Wide occupation of vegetation types has been noted also in the Rockhampton area to the north (Longmore 1978). Vernon (1976) and Roberts (1979) both note that peregrines favour mountainous areas with exten- sive cliffs and rocky outcrops. Examination of re- cords used to construct Fig. 1 indicates that this is essentially correct with some modification. Cer- tainly peregrines are well represented in moun- tainous areas as they have been seen on 1 1 of the 14 major mountain systems. However, they are also frequently observed in coastal districts where they may be locally abundant (Cooloola; Roberts and Ingram 1976). Examination of inland localities where peregrines are regularly encountered indi- cates an association with cliffs, gorges, and out- crops. Similarly, coastal records involve areas where eroded high dunes/coastal cliffs (Fraser, Moreton and North Stradbroke Islands), subcoastal high- lands (MacPherson Range-Gold Coast) or isolated peaks (Mt. Cooroy-Peregian, Pumicestone Passage - Glasshouse Mountains) are found nearby. 81 Raptor Research 18 ( 3 ): 81-91 82 G.V. Czechura Vol. 18, No. 3 Figure 1. Distribution of Falco peregrinus macropus in southeastern Queensland based on both published and unpub- lished sightings. Breeding, Density and Movements Twenty-four active eyries (eggs and/or adults plus young present) are known from southeastern Queensland. In addition, several areas containing suspected eyries have yet to be examined and 1 eyrie previously known to be active was inactive. Most eyries were located within major range sys- tems although 6 outlying sites are known. With the exception of 1 eyrie located on a high coastal foredune, vertical or subvertical rock faces along exposed cliffs or along gorges were utilized. Rock faces were variously composed of granite, trachyte, basalt or sandstone. The dune nest was situated on exposed sandrock-fossil hardpan. Individual eyries were placed on ledges, crevices or shallow caves (Fig. 2 A,B) between 30-270 m above ground level. The surrounding vegetation was either subtropical rainforest, open-forest or woodland. Most eyries appeared to have been active for some time. One located within the northern More- ton region was active since the early 1940’s, al- though peregrine records within this area indicate at least 50 yr occupation of the site. Activity as- sociated with another Moreton region eyries indi- cates that it has been active for about 60 yr. The earliest records available for the southern Moreton region are from the early 1940’s, and mid-1950’s for the western Moreton region. Only very recent records are available for the Wide Bay-Burnett re- gion. Observations made wihin the northern Moreton region suggest that breeding starts mid-August or early September. Beruldsen (1980) records a nest- ing season of “July to October, sometimes November in the south, and April to June in the north”. The earliest known egg-laying occurred in late July (1980) and the latest early November (1968). The latter cases appears somewhat anoma- lous and may represent either a late breeding or a replacement clutch. Display was noted during Oc- tober and 2 fledglings were present during De- cember. Little activity had been detected during September of that year. Pre-egg-laying display flights were typical of those used by peregrines elswhere and consists of mixtures of components such as High-circling, Figure-of-eight, Flight- rolling and Z-flight (Cramp and Simmons 1980; Fall 1984 Peregrine Falcon in Queensland 83 Table 1. Summary of available published sightings of Peregrine Falcons in Southeastern Queensland. Locality Source Callide Dam Zillman 1974 Sandy Cape Makin 1968 Fraser Island Vernon and Barry 1972 Mt. Walsh Frauca 1970 Maryborough Anon. 1972, Jones 1981 Auburn River Darling Downs Naturalist Dec. 1978:43* Cooloola Roderick 1975, Roberts and Ingram 1976; Dwyer et al. 1977 Teewah Creek Ingram 1972 Noosa Heads Wheeler 1959 (probable) Jimna Q.O.S. July 1978:2* Kilcoy Shire McEvoy et al. 1979 Blackall Range Czechura in press Maleny Czechura 1970, Q.O.S. Jan. 1975:2 Conondale Range Roberts 1977; Czechura in press Glasshouse Mountains Jack 1941; Fien 1966; MacArthur 1978 Pumicestone Passage Mayo 1934; MacArthur 1978 Redcliffe Q.O.S. May 1974:3 Crows Nest Q.O.S. Oct. 1977:3 D’ Aguilar Range Illidge 1923; Vernon 1976 Pinkenba Q.O.S. Nov. 1982:4 Lytton Q.O.S. Nov. 1982:2 Bardon a.S. May 1974:3 Stones Corner Q.O.S. Nov. 1982:2 Murphy’s Creek Lord 1956 Pt. Lookout Q.O.S. May 1977:4 North Stradbroke Is. Vernon and Martin 1975 Cecil Plains Q.O.S. June 1979:2 Cooper’s Plains Q.O.S. March 1976:3 Redwood Park Q.O.S. July 1978:3 Cunningham’s Gap Vernon 1976 Dalrymple Ck. Q.O.S. June 1977:2 Tweed R. District Keast 1944 Warwick district Kirkpatrick 1967 Emuvale Q.O.S. Sept. 1977:2 Stanthorpe Passmore 1982 Lamington N.P. Robertson 1948 Binna Burra Wheeler 1973; Q.O.S. July 1979:4 * Newsletters are cited in table only. ‘Q.O.S.’ refers to Queensland Ornithological Society Newsletter. Monneret 1974; Ratcliffe 1980). In addition, a flight termed herein the V-flight, has been ob- served in which a circling or flying peregrine sud- denly stoops with wings closed, terminates the stoop by spreading its wings and regains altitude using a combination of momentum and flapping flight (Fig. 3). The speed at which the stoop is terminated and altitude regained often leaves the impression of a stoop followed by a ‘bounce’. The V-flight usually followed a period of High-circling, linear flight or undirected activity. Several flights may be con- ducted in quick succession. All display flights were 84 G.V. CZECHURA Vol. 18, No. 3 C D Figure 2: A. Ledge eyrie (e), eastern Moreton region; adjacent roosts (r) are also indicated. B. Cave eyrie (2), eastern Moreton region; perched peregrine (1) and adjacent roosts are indicated. The location of this eyrie is shown by its entrance. C-D. Peregrine hunting area (approx. 4 km SW Maleny). This area has been regularly used since 1970. Note different vegetation types present (r- rainforest, t-tall open-forest, p-pasture, w-regrowth). Fall 1984 Peregrine Falcon in Queensland 85 Figure 3. The ‘V-flight’ display. The display commences. (A) from earlier circling or similar activity. The falcon abruptly stoops with wings closed (B), terminates the flight (C) by spreading the wings and regains altitude (D) using momentum and later flapping flight. accompanied by much vocalization. Copulation usually occurred late during the display period and on areas surrounding the nest (ledges, projections of the cliff-face or adjacent trees). Little information is available concerning clutch size. P. Olsen (pers. comm.) has examined 3 clutches (1 questionably from sotheastern Queens- land). All consisted of 3 eggs. Indirect evidence, such as the number of fledglings at active eyries, suggests that a clutch size of 3 is usual (G. Geruldsen pers. comm.; pers. obs.). Typically 2 young fledge (Table 2). The maximum number of fledglings ob- served at a number of sites is 3 (pers. obs. ; P. Slater pers. comm.; D. Evans pers. comm.,) suggsting either high productivity or occasional larger clutches. Olsen and Olsen (1979) record a mean clutch size for Queensland peregrines of 2.5 pre- 1947 and 3.1 post- 1947. Savidge (in Mathews 1916) records cliff-face nesting in the Clarence River dis- trict of northeastern New South Wales and col- lected the following successive clutches from 1 pair of falcons; 16 August, 3 eggs; 13 September, 3 eggs; 14 October, 2 eggs. Data from southeastern Queensland appear con- sistent with similar data from southeastern Au- stralia. The presumed clutch size of 3 in southeast- ern Queensland compares favourably with both the State means (above) and the combined means for New South Wales, Victoria, South Australia and Tasmania (pre-1947, 3.0; post- 1947, 2.7; data from Olsen and Olsen 1979). Olsen (1982) did not find any significant correlation between clutch size and latitude, longitude or temperature. Similarly, com- parison of the mean numbers of fledglings of the 2 Moreton region eyries (2.13, 2.25; Table 2) indi- cates that these values are within the range for numbers of young at successful eyries in New South Wales ( 2 . 2 ), Victoria (2.1), South Australia (2.2) and Tasmania (2.5) (data from Pruett-Jones et al. 1981; Olsen and Olsen in press). Pending the completion ot survey work currently in progress, only approximate values of peregrine density over the entire region are available. Esti- mates, based on known pairs in the Moreton region, indicate a density of about 1 pair/2600 km 2 , while taking suspected pairs into consideration a value of 1 pair/ 1500 km 2 is suggested. These values com- Table 2: Fledgling number at 2 adjacent northern Moreton Region Eyries 1968 - 1982. Numbers of Fledglings Observed Year Eyrie A Eyrie B 1968 2 * 1969 2 * 1970 3 * 1972 3 * 1976 2 * 1977 1 * 1979 2 2 1980 * 3 1981 * 2 1982 2 2 Mean 2.13 2.25 * - No data available 86 G.V. CZECHURA Vol. 18, No. 3 pare with a density of 1 pair/ 100 km 2 for one area under study. Distances between neighboring eyries range from 4.8 - 65 km (mean 40.9, N = 221 km). The above density values are tentative. This un- certainty reflects the difficulty in locating alternate nesting sites (e.g., stick nests) in dense forest (rain- forest, tall open-forest) and poor accessibility to some highland areas supporting suitable cliff faces. The current estimates indicate a nesting density well below that of Victoria (1 pair/600 - 800 km 2 , White et al. 1981) and slightly higher than Tas- mania (Olsen and Olsen in press). Storr (1983) considers F. p. macropus to be nomadic and evidently migratory over much of Queensland. He noted that most records involved the period April-October. Monthly observations at several more accessible Moreton region eyries strongly suggested that breeding birds are rela- tively sedentary with roosts being maintained around the eyrie outside the breeding season. Ob- servations made by Jones and Bren (1978) and Olsen and Olsen (in press) indicate the same in southeastern Australia. Hunting is less frequent but conducted over much the same area as used dur- ing the breeding season. In general, it seems that the apparent nomadism of peregrines may be at- tributable to the inconsicuousness of adults around eyries outside the breeding season and movements of immature birds. Locally high de- nsities have been reported (Elks in Roberts and Table 3. Prey recorded for the Peregrine Falcon ( Falco peregrinus macropus ) in Southeastern Queensland. Prey Items Source Insects Ortho ptera Odonata Birds Prion (Pachyptila sp. Cormorants (Phalacrocorax spp.) Sacred Ibis ( Threskiomis aethiopicus) Black Duck (Anas superciliosa) Grey Teal (Anas gibberifrons) Australian Kestrel (Falco cenchroides) Stubble Quail (Coturnix novae zelandiae) Brown Quail (Coturnix australis) Red-kneed Dotterel (Erythrogonys cinctus) Red-necked Stint (Calidris ruficollis) Feral Pigeon (Columba liva) Crested Pigeon (Ocyphaps lophotes) Bar-shouldered Dove (Geopelia humeralis) Rainbow Lorikeet (Trichoglossus haematodus) Scaly-breasted Lorrikeet (. Trichoglossus chlorolepidotus ) Pale-headed Rosella (Platycercus adscitus) White-throated Needle-tail (Hirundapus caudacutus) Black-faced Cuckoo-shrike (Coracina novaehollandiae) Lewin Honeyeater (Meliphaga lewinii ) Noisy Friar-bird (Philemon corniculatus) Noisy Miner (Manorina melanocephala) Yellow-faced Honeyeater (Lichenostomus chrysops) Common Starling (Stumus vulgaris) P. Slater pers. comm. Pers. obs. C. Corben pers. comm. Mayo 1934 Czechura 1971, pers. obs. R. Lutkins pers. comm. R. Lutkins pers. comm. B. Cowell and G. Czechura obs. 1 Czechura 1979 Czechura 1979 G. Roberts pers. comm. C. Corben and G. Czechura obs. C. Corben pers. comm., D. Evans pers. comm. P. Veerman pers. comm, pers. obs. pers. obs., D. Evans pers comm., C. Corben pers. comm. pers. obs. 1 , D. Evans pers. comm. Prey remains at eyrie G. & R. Czechura obs. 1 pers. obs. pers. obs. 1 pers. obs. 1 pers. obs. 1 pers. obs. pers. obs. 1 1 Includes observations made at eyrie during breeding season. Fall 1984 Peregrine Falcon in Queensland 87 Ingram 1976) but as with most reports, it is not known if these involve adults or immatures. Im- matures once independent, rarely remain in the vicinity of the eyrie for longer than 4-8 weeks approximately, although lone birds may take up residence in areas rarely frequented by the adults (pers. obs.). Otherwise little is known of movements or fate of the majority of immature birds. Hunting and Prey - Peregrines were observed hunting in a variety of habitat and landscape types. Some regularly hunted over both very open (mudflats, waterways, pastureland) and densely vegetated (rainforest, tall open-forest, heathland) areas (Fig. 2 C, D). Presumably, hunting areas were determined by the location of nesting sites. Prior to the advent of European settlement in southeastern Queensland, peregrines were largely assocated with forested habitats. Rainforest vegeta- tion was more extensive in coastal and subcoastal districts than at present (Illidge 1925; Francis 1970). Indeed, Cade (1982) noted that Australian populations of F. peregrinus show modifications of the feet and beak typical of “forest” races of the peregrine, F. p. peregrinator (India), F. p. ernesti (New Guinea) and F. p. nesiotes (Figi) and the two large, forest-dwelling species, Orange-breasted Falcon ( Falco deiroleucus ) and New Zealand Falcon ( Falco novaeseelandiae ). Similarly, Pruett-Jones et al. (1981a) have commented on modifications of hunting techniques for dense woodland and forests in Victoria. Birds were the chief prey (Table 3). Brief de- scriptions of some hunting flights are given by Mayo (1934) and Czechura (1970, 1971). Compari- son of published and unpublished observations with the descriptions of Treleaven (1977), Ratcliffe (1980) and Cade (1982) indicate most hunting con- sists of a period of “still hunting” or “waiting on” followed by the traditional stoop or direct pursuit. “Still hunting” (Fig. 4-1 A) involves the falcon launching an attack from a perch, such as an emer- gent tree in rainforest, on passing birds. On leaving the perch, the peregrine either gained altitude and then stooped onto the prey, made a level dash to- wards it (Mayo 1934; Czechura 1971) or stooped directly onto it. “Waiting On” (Fig. 4- IB) involves the raptor initially spending some time circling and/or engaged in active flight before stooping. The actual stoop (Fig. 4-2 B) is usually conducted with wings closed or partly closed in a rather shal- low angle of attack. The final stages of the stoop may result in complex aerial manoeuvres as prey attempts to evade the falcon (Fig. 4-1 B). Once the prey is struck by the peregrine, a loop may be per- formed to retrieve the body (Fig. 4-2B) or the bird may be simply seized and carried. Direct pursuit usually culminates in the peregrine seizing the prey. Under special circumstances other hunting techniques were employed. “Solitary flushing” may be employed against ground-dwelling quail (Czechura 1979). The peregrine will make rapid, low-level passes above the vegetation sheltering the quail. If quail flush, direct pursuit will result. Peregrines, at other times, will “hawk” flying insects by leisurely circling amongst the insects and snatching them out of the air or snatch birds shel- tering on the ground as they pass overhead, e.g., waders on mudflats. It is difficult to determine hunting efficiency of peregrines. On many occasions a falcon will indulge in numerous attacks for up to an hour before a successful kill is made. Many attacks, however, do not appear to be pressed with determination (low intensity attacks, Treleaven 1977) e.g., the falcon breaks off early, stoops are short and relatively slow. During such times, and sometimes after feeding, “playful” attacks are made on large birds such as ibis ( Threskiomis spp.) and Torrsian Crow (i Corvus orru). Under the circumstances, lone crows or ibises are stooped on, with the peregrine often looping around the intended victim and then flying away. Similarly, flocks may be attacked with the apparent objective of breaking them up into smal- ler units. Bouts of such playful behaviour are in- terspersed with periods of soaring, slow flying and perching. Attacks on flocks of birds are usually unsuccessful if the flocks maintain their structure (Fig. 4- 1C). Lone birds that attempt to leave the flock often are very quickly captured (Fig. 4-2C). Fruit pigeons and lorrikeets will often attempt to out-manoeuvre the falcon and seek shelter in the canopy of nearby trees by perching or flying through them. Frith (1942) reported such be- haviour among fruit pigeons in northern New South Wales but notes one case where the pursuing peregrine pressed its attack below the forest canopy. While successful attacks have been ob- served on lorikeets ( Trichoglossus spp.) and hon- eyeaters, no successful attacks have been reported on either Topnot Pigeon (Lopholaimus antarcticus ) or White-headed Pigeon ( Columba leucomela) flocks. 88 G.V. CZECHURA Vol. 18, No. 3 Figure 4. Peregrine Falcon (Falco peregrinus) hunting behavior. 4. 1 Hunting over rainforest and pasture-regrowth area near Maleny (profile taken from transect across part of the hunting area shown in Plate 1 C-D). A. Unsuccessful (Plow intensity) attack on a flock of Topknot Pigeons (flight path C) leaving rainforest canopy. The adult female peregrine was perched in an emergent Ficus sp. and returned after this attack.' B. Successful attack on an unidentified honey-eater (D) after a period of soaring. The honeyeater attempted to climb, then dive away from the falcon prior to its capture (x). Plucking and feeding was conducted on the perch atop the emergent Ficus sp. This attack was conducted approximately 15 mins after attack A. 4.2 Successful hunt over woodland - pasture - low riverine rainforest near Woodford. A. Feeding flock of lorikeets were attacked by an adult female peregrine (B) after leaving the central tree. The flock, except one bird (C) fled through the canopy of adjacent trees. Bird C was struck by the falcon, caught after a rapid loop, then carried. Fall 1984 Peregrine Falcon in Queensland 89 Although very little is known of hunting and prey species of peregrines in the region during early settlement, observations made by Savidge (in Mat- thews 1916) in the Clarence River district of north- eastern New South Wales suggest little change has taken place. Savidge records the folio wng prey, Black Duck (Anas superciliosa). Rainbow Lorikeet (Trichoglossus haematodus). Pale-headed Rosella (Platycercus abscitus), Australian Magpie-lark (Gral- lina cyanoleuca ) Feral Pigeon (Columba livia) and Feral Chicken (Gallus gallus ). All but G. cyanoleuca and G. gallus have been recorded among prey from southeastern Queensland (Table 3). Interactions with Other Raptors - Interaction between the Australian Hobbie (Falco longipennis ) and peregrines occur in many areas with the excep- tion of heavily timbered and some upland areas (Czechura in press). Both falcons may be found hunting in the same areas on occasion (e.g., Wood- ford, Caboolture), especially when lorikeets are abundant. At these times peregrines largely hunt the Rainbow Lorikeet (Trichoglossus haematodus) and Scaly-breasted Lorikeet (Trichoglossus chlorolepi- dotus), while Australian hobbies hunt T. chlorolepidotus and the smaller Little Lorikeet (Glos- sopsitta pusilla ). The Brown Falcon (Falco berigora) occurs with peregrines in many areas with the ex- ception of densely timbered country. Interactions between Brown and Peregrine Falcons appear to be mildly aggressive. Brown Falcons will often leave hunting areas after the appearance of peregrines. At other times peregrines may make 1 or 2 casual stoops at flying Brown Falcons or Brown Falcons may stoop at perched peregrines. The Australian Kestrel (Falco cenchroides) comes into contact with peregrines in the same habitats as Brown Falcons. Kestrels readily mob perched peregrines, while Czechura (1970) has reported a possible ‘play’ en- counter. On one occasion a kestrel was among prey brought to an eyrie (Table 3). Peregrines have been observed mobbing the Whistling Kite (Haliastur sphenurus ) on 2 occasions along Pumicestone Passage. Both of these involved the same immature female peregrine. Otherwise observations are restricted to encounters near eyries. On several occasions the Wedge-tailed Eagle (Aquila audax ) and once a Grey Goshawk (Accipiter novaehollandiae) were mobbed by one or both fal- cons as they approached eyries. Mortality and Conservation - Little is known of natural mortality among peregrines in southeast- ern Queensland, although one was found dead after a hailstorm in the Brisbane area (Q.M. or- nithological records). The most significant cause of mortality appears to be human persecution. Pigeon fanciers have destroyed adults and interfered with eyries in the eastern Moreton region. Some falcons certainly fall victim to general persecution of rap- tors. Disturbance at eyries also results from sight- seers, bushwackers and illegal egg-collectors. The nature and extent of pesticide effects within the region are poorly known. Olsen and Olsen (1979) found greater than 20% eggshell thinning attributable to D.D.T. in clutches from southeast- ern Queensland; this compares with a State mean of 3.6%. Shell thinning of 15-20% is critical - affected eggs would not be expected to withstand incubation (Newton 1979; Ratcliffe 1980). No peregrines have come to the Small Animal Clinic, Department of Veterinary Science, University of Queensland, suf- fering from pesticide poisoning (W. Rooke pers. comm.), but the Clinic has received other diurnal raptors suffering from pesticide poisoning. Some recent developments in the patterns of pesticide use in southeastern Queensland are of concern. Heliothis moths are serious crop pests (Broadley 1977) and recent failure of a number of synthetic pyrethrins used in their control has led to renewed use of organochlorines in a number of areas, while serious outbreaks of armyworms (Pseudaletia spp., Spodoptera sp.; Broadley 1978, 1979) in southern subcoastal pasturelands have necessitated use of pesticides (particularly via aerial application), where their usage has traditionally been of a low level. Although a number of eyries are within the existing national park-reserve system, there are no specific conservation/management programmes in operation. The species is protected under the pro- visions of the Fauna Conservation Act of 1974. Acknowledgments I thank Victor Bushing, David Evans, Peter Hughes, Ted Johansen, Kathleen MacArthur, Gary Norwood, Tony Palliser, Chris Pollitt, Gary Silk, Peter Slater, Phillip Veerman, Ian Vena- bles and Eric Zillmann for information used herein. For field assistance, I thank Robin Czechura and Gunter Maywald, Assis- tance in manuscript preparation was kindly provided by Gordon Beruldsen, Chris Corben (Department of Forestry, Queensland), Glen Ingram (Queensland Museum), Scott Mooney (National Parks and Wildlife Service, Tasmania). Jerry Olsen, Penny Olsen (Division of Wildlife Research, C.S.I.R.O.), Greg Roberts and Clayton White (Brigham Young University). 90 G.V. CZECHURA VOL. 18, No. 3 Literature Cited Anon. 1972. Birds within five miles of Maryborough. Wambcdirrum 6(4): 3-4. Barnard, C.A. and Barnard, H.G. 1925. A review of the birdlife on Coomooboolaroo Station, Duaringa district, Queensland, during the past fifty years. Emu 24:252-65. Beruldsen, G. 1980. ‘A Field Guide to the Nests and Eggs of Australian Birds’. (Rigby, Adelaide, 448 pp.). Bijleveld, M. 1974. ‘Birds of Prey in Europe’ (Macmil- lan, London. 263 pp.). Broadbent, K. 1889. Birds of the central part of Queensland. Proc. R. Soc. Qd. 5:14-31. Broadley, R.H. 1977. Heliothis . . . serious agricultural pests in Queensland. Qd Agric.J. l03(6):536-45. Broadley, R.H. 1978. The lawn armyworm ... a seri- ous rural and urban pest. Ibid 104(3): 232-6. 1979. Year of a massive armyworm problem. Ibid. 105(6):573. Brown, L.H. 1970. ‘African Birds of Prey’. (Houghton-Mifflin, Boston. 320 pp.). Cade, T.J. 1969. The status of the peregrine and other falconiformes in Africa, pp. 289-321. In Hickey, J.J. (ed.) ‘Peregrine Falcon Populations. Their Biology and Decline’. (University of Wisconsin Press, Madison. 596 pp.) Cade, T.J. 1982. ‘Falcons of the World’ (Cornell Univer- sity Press, Ithaca. 192 pp.). Chaffer, N. 1974. Black-cheeked Falcon. Emu 43(4):251-253. Clunie, F. 1972. A contribution to the natural history of the Fiji Peregrine. Notomis 19:302-22. 1976. A Fiji Peregrine (Falco peregrinus) in an urban-marine environment. Ibid 23(l):8-28. Cramp, S. and Simmons, K.E.L. 1980. ‘Handbook of the Birds of Europe, the Middle East and North Africa. Vol. 2. Birds of Prey to Bustards’. (Oxford University Press, Oxford. 570 pp.). Czechrua, G.. 1970. The Peregrine Falcon (Fako pereg- rinus) at Maleny (S.E.Q.). Sunbird 1(4): 102-3. 1971. Field notes on hunting methods of falcons. Ibid. 2(4):68-72. 1979. Observations on quail-hunting strategies in some Australian raptors. Ibid. 10(3°4): 59-66. in press. The raptors of the Blackall- Conondale Ranges and adjoining lowlands. Dwyer, P.D., Kikkawa, J. and Ingram, G.J. 1979. Habitat relations of vertebrates in sub- tropical heathlands of coastal southeastern Queens- land. pp. 281-99. In R.L. Specht (ed.). ‘Ecosystems of the World 9A. Heathlands and Related Shrublands. Descriptive Studies. (Elsevier, Amsterdam. 497 pp.). Fien, I. 1966. Falcon at Glasshouse Mountains. Queens- land Bird Notes 2(5): 4. Francis, W.D. 1970. ‘Australian Rainforest Trees’. (Au- stralian Government Printer, Canberra. 468 pp.). Frauca, H. 1970. Some notes on the mammals and birds of Mount Walsh National Park, Biggenden, Wide Bay area, Queensland. Wambaliman 4(5): 4- 13. Frith, H.J. 1942. Noteson the pigeons of the Richmond River, N.S.W. Emu 89-99. Groves, R.H. (ed.) 1982. ‘Australian Vegetation’. (Cambridge University Press, Cambridge, 449 pp.). Hickey, J.J. (ed.) 1969. ‘Peregrine Falcon Populations. Their Biology and Decline’ (University of Wisconsin Press, Madison, 596 pp.). Illidge, R. 1923. Insects and birds observed during Cedar Creek and D’ Aguilar Range excursion. Qd Nat. 4(2): 34-5. 1925. The Blue-faced Lorilet also cal- led Coxen’s Fig Parrot. Ibid 4(6): 133-4. Ingram, G.J. 1972. Notes on the feeding of White- browed Woodswallows (Artamus superciliosus). Sunbird 3:64-5. Jack, N. 1941. Some birds and mammals of the Glassh- use Mountains district. Qd Nat. 1 1(6): 127-32. Jones, M.V. 1981. Birds of the Maryborough district, Queensland, 1972-1980. Aust. Bird Watcher 9(1): 1-13. Jones, S.G. and Bren, W.M. 1978. Observations on the winterig behaviour of Victorian Peregrine Falcons. Ibid 7(6): 198-203. Keast, A. 1944. A inter list from the Tweed River dis- trict, N.S.W., with remarks on some nomadic species. Emu 43:177-87. Kirkpatrick, T.H. 1967. Mammals, birds and reptiles of the Warwick district, Queensland. 2 Birds. Qd. J. Agric. Animal Sci. 24:81-91. Longmore, N.W. 1978. Avifauna of the Rockhampton area, Queensland. Sunbird 9(3/4) :25-53. Lord, E.A.R. 1956. The birds of Murphy’s Creek dis- trict, southern Queensland. Emu 56:100-28. McEvoy, J.S., McDonald, K.R. and Searle, A.K. 1979. Mammals, birds, reptiles and amphibians of the Kilcoy Shire, Queensland. Qd J. Animal Sci. 36(2): 167-80. Mac Arthur, K. 1978. ‘Pumicestone Passage. A Living Waterway’ (Author, Caloundra. 141 pp.). Makin, D. 1968. Birdsof Sandy Cape, Fraser Island. Qd. Nat. 19:31-42. Mather, P. (ed.) 1976. ‘The National Estate. Moreton and Wide Bay-Burnett Regions’. (Queensland Museum, Brisbane 272 pp.). Matthews, G.M. 1916. ‘The Birds of Australia. Vol. 5’ (Witherby, London. 440 pp.). Mayo, W.M. 1934. Bird notes of Bribie Island and Pumice Stone Passage. QdNat. 9(1): 12-6. Monneret, R.J. 1974. Repertoire comportmental du Faucon pelerin. Falco peregrinus. Hypothese explicative des Man- ifestations Adversives. Alanda 42:407-28. Newton, I. 1979. ‘Population Ecology of Raptors’ (Poyser, Calton. 430 pp.) Norris, K.C., Emison, W.B. and Bren, W.M. 1977. A preliminary survey pf the population of Peregrine Fal- cons in Victoria. Emu. 77:86-7. Fa i t, 1984 Peregrine Falcon in Queensland 91 Olsen, J., Olsen, P. and Jolly, J. 1979. Observation on interspecific conflict in the Peregrine Falco peregrinus and other Australian falcons. Aust. Bird Watcher 8(2):51-7. Olsen, P.D. 1982. Ecogeographic and temporal varia- tion in the eggs and nests of the Peregrine, Falco pereg- rinus, (Aves Falconidae) in Australia. Aust. Wildl. Res. 9:277-91. Olsen, P. and Olsen, J. 1979. Eggshell thinning in the Peregrine, Falco peregrinus, in Australia .Ibid. 6:2 17-26. 1981. D.D.T. Peregrines in peril. RAOU Newsletter 49:1-3. in press. Population studies of the Peregrine in Australia. (Proceedings of the I.C.B.P. Conference on Birds of Prey, Thessaloniki, Greece, 1982). Passmore, M.D. 1982. Birds of Stanthorpe, Queens- land, and its northern environs, 1972-1981. Ami. Bird Watcher 9(7):277-237. Pruett -Jones, S.G., White, C.M. and Devine, W.R. 1981a. Breeding of the Peregrine Falcon in Victoria, Australia. Emu 80 suppl:253-269. Pruett -Jones, S.G., White, C.M. and Emison, W.B. 1981b. Eggshell thinning and organochlorine residues in eggs and prey of Peregrine Falcons from Victoria, Australia. Ibid. 281-287. Ratcliffe, D. 1980. ‘The Peregrine Falcon’ (Payser, Calton, 416 pp.). Roberts, G.J. (ed.) 1977. ‘The Conondale Range - the case for a National Parks’ (Queensland Conservation Council, Brisbane, 86 pp). 1979. ‘The Birds of South-east Queensland’ (Queensland Conservation Council, Brisbane. 50 pp.). and Ingram, G.J. 1976. An annotated list of the land birds of Cooloola. Sunbird 7:1-20. Robertson, J.S. 1948. Birds of the 1947 Queensland camp-out at Binna Burra, Queensland. Emu 47:373-88. Roderick, G. 1975. Bird observations in the Cooloola area, 12-20 August 1972. Qd Nat. 21:58-9. Steyn, P. 1982. ‘Birds of Prey of Southern Africa’ (David Philip, Cape Town. 309 pp.). Storr, G.M. 1973. List of Queensland birds. Spec. Publ. W. Aust. Mus. 5:1-177. Vernon, D.P. 1968. ‘Birds of Brisbane and Environs’ (Queensland Museum, Brisbane 131 pp). 1976. Birds pp. 74-97. In Mather, P. (ed.) ‘The National Estate. Moreton and Wide Bay- Burnett Region’ (Queensland Museum, Brisbane. 272 pp.). and Barry, D.H. 1972. Birds of Fraser Island and adjacent waters. Mem. Qd Mus. 16(2):223-32. and Martin, J.H.D. 1975. Birds of Stradbroke Island. Proc. R. Soc. Qd 86(1 1):61-72. Wash, B.P. 1978. Observations on Peregrine Falcons nesting in Werribee Gorge, Victoria. Amt. Bird Watcher 7(5): 138-142. Wheeler, R. 1959. The R.A.O.U. camp-out at Noosa Heads, Queensland, 1958 .Emu 59:229-249. 1973. The birds of ‘Green Mountains’. Aust. Bird Watcher 4(8):257-269. White, C.M., Pruiett-Jones, S.G. and Emison, W.B. 1981. The status and distribution of the Pereg- rine Falcon in Victoria, Australia. Emu 80 suppl.:270- 280. Zillmann, E.E. 1974. Birds at Callide Dam. Wambaliman 8(5):6-8. Queensland Museum, Gregory Terrace, Fortitude Valley. Q. 4006. Received 15 June 1983; Accepted 1 June 1984. Attention RRF Members Past and Present!! The Raptor Research Foundation, Inc., is approaching its 20th Anniversary. In honor of this memorable occasion, I am compiling a twenty-year history of the Foundation to be presented in Sacramento at the 1985 annual meeting. In addition, plans are to compose a monograph detailing the Foundation’s history from beginning to present. I request the assistance of you, the membership, both past and present, in accomplishing this task. Please contact me if you have any pertinent information in your files, such as photographs, correspondence, etc., that you would be willing to loan to me. All such material will be acknowledged in publications, of course, and I will make copies of the materials for my use and return the originals immediately. If you have anything you wish to contribute, please contact me as follows: Jimmie R. Parrish, Department of Zoology, 159 WIDB, Brigham Young University, Provo, Utah 84602, USA. SPRING AND FALL MIGRATIONS OF PEREGRINE FALCONS IN CENTRAL ALBERTA, 1979-1983, WITH COMPARISONS TO 1969-1978 Dick Dekker ABSTRACT - In central Alberta, 1979-1983, 339 sightings of migrating Peregrine Falcons ( Falco peregrinus) were recorded between 15 April and 31 May. Mean sightings per hour afield were 0.23 for the entire period and 0.29 for the main migration period 4-23 May, respectively 1 1 and 19% lower than for 1947-1978. Mean early dates, mid-dates and mean late dates for adults were respectively 6, 7 and 2 days in advance of immatures, and nearly identical to 1969-1978. Fall sightings were similarly scarce as in 1969-1978, totalled 24, and occurred from 1 7 September to 3 October. In fall, the ratio of adults to immatures was roughly 1:3 and in spring 1:1. The success rate of 191 hunting attempts was 9.4%. Since the 1950’s, the Peregrine Falcon {Falco peregrinus ) has suffered serious population declines in North America (Hickey 1969). As a breeding bird it was extirpated in southern and central Al- bertaL by the early 1970’s (Fyfe et al. 1976), although captivity-raised and released falcons nested in Ed- monton and Calgary in 1982 and 1983 (G. Erickson, Alberta Fish and Wildlife Division, pers. comm.). In spring and fall, northern peregrines migrate through central Alberta (Dekker 1979). Field surveys along the Atlantic and Texas coasts have recently shown substantial increases in the number of peregrines sighted during fall migra- tions (F.P. Ward, pers. comm.). This paper presents data on the characteristics of migrating peregrines in central Alberta from 1979 to 1983. Pooled data for these 5 yrs can be juxtaposed to data from 1969 to 1978 when I did similar Field studies (Dekker 1979), although data for 1969-1973 are incomplete and based on less expertise. The most recent 10 yrs allow valid comparisons of number of sightings/h, age ratios and timing of migrations. Study Area and Methods The study area was a crescent-shaped strip of grainfields and open pastures, roughly 10x2 km in size, bordered by Beaverhill Lake, that attracted numerous waterfowl and shorebirds in mig- ration. In searching for peregrines no set procedures were fol- lowed, although methods were similar to thoseof 1969-1978. Each day afield I hiked 5-25 km, frequently pausing to scan through 10x50 binoculars. I often sat in a parked car and used a20-40X telescope as well as binoculars. Many resting peregrines sitting on fence posts or on the ground were watched until they left of their own accord. Flying peregrines were observed for as long as they remained visible. Alarm behaviour of prey species often alerted me to the arrival of peregrines. The study area was visited from early March to early December. Pooled for 5 yrs, field days totalled 167 and 79 respectively during 15 April -31 May and 1 September- 15 Ocotber. Field days lasted 3-17 and averaged 9 h within varying time frames. About 85% of peregrines sighted in spring were positively identified; distant large falcons that I could not identify were assumed to be peregrines unless I suspected them of being Prairie Falcons (Falco mexicanus), that are occasion- ally seen in the study area in spring (Dekker 1982). During fall, when peregrines are uncommon in the study area and both the Prairie Falcon and the Gyrfalcon (Falco rusticolus) occur (Dekker 1983), all sightings of unidentified large falcons were deleted. (For criteria used in field identification see Dekker 1977). I paid little attention to the problem of duplicate sightings other than to delete obvious ones. For 1969-1978 1 tabulated maximum and minimum sightings that show a duplication rate of 2.4. This indicates the magnitude of the problem but is only an estimate. The so-called maximum numbers of 1969-1978 “include duplicate counts ex- cept the most obvious ones”, (Dekker 1979:297) and correspond to sightings in this study. Data on huntingare for 1980-1983 only; 1979 observations were presented elsewhere (Dekker 1980). Methods in recording foraging behavior were the same as in 1969-1978. Observations were written down during or at the end of the day. Results and Discussion Numbers Sighted and Timing of Migrations - In spring, peregrines were seen from 20 April to 31 May (Fig. 1 ). Sightings pooled for 5 yrs ranged from 0 to 21/d and totalled 339 (Table 1). Mean numbers of sightings/h were 40-60% higher in morning and evening than between 1200Hand 1500H(Table 2). Earliest dates ranged from 20 to 30 April. Mean early dates for adults and immatures respectively, ranged from 20 April to 7 May and from 1 to 9 May. Early arriving falcons appeared to pass quickly. They often hunted over the still-frozen lake and rested on the ice far from shore. I suspect that all April sightings of unidentified falcons involved adults. That assumption would advance their mean early date to 25 April, 9 d ahead of immatures (Table 3). Mean late sightings of adults and imma- tures respectively, ranged from 17 to 27 and 19 to 31 May. Mean late dates and mean mid-dates (half of total sightings) were nearly equivalent to those of 1969-1978 (Table 3). To check for the presence of summering falcons, the study area was visited about 4 times/month 92 Raptor Research 18(3):92-97 Fall 1984 Peregrine Falcon Migration 93 Adults cn o milmil r Ti rh " i— f r-n Immatures cn O i i i i 1 i i i 1 1 n-lT ~1 n rf pi 20- cn CD sz 'L 15- _C cn £ lo-E 5 5^ o I 1- =E- — — — i - p ~ I— 20 April 25 1 May 5 10 15 20 25 30 Figure 1. Peregrines sighted during spring migration in unidentified age class. (range 3-7) in June, July and August. One pereg- rine each was seen on 19 July 1980 and 2 June 1982. Both were immatures. The June sighting probably involved a late migrant, but the July bird may have originated from a captive-breeding program with releases in central and southern Alberta (G. Erickson, Alberta Fish and Wildlife Division, pers. comm.). I saw no evidence that captive-bred pereg- rines occurred in the study area during spring mig- ration. Data for the autumn were similarly limited as in 1 974- 1978 and ranged from 1 7 September to 3 October. Age and Sex Ratios - The proportion of adults and immatures in spring differed from 1974-1978 (Table 4). I attribute that difference to the follow- ing change in my criteria for identification. In 1969-1978 I differentiated the age groups mainly by dorsal coloration; adults are ashy-blue, imma- tures brownish. However, I have found that dorsal color is not always a reliable fieldmark as some adult peregrines look blackish-brown dorsally, resembl- ing the spring immatures that are often light- chested (Dekker 1979). Since 1979, 1 have included all dorsally blackish falcons in the unidentified central Alberta. Total sightings include peregrines of category unless I saw their ventral markings, barred in the adult, streaked in the immature. The more typically-colored adults are easily identified in flight under good conditions. The proportion of adults (29%) was remarkably close to that of 1974- 1978 (28%) but differed from 1969-1973 (38%). The adult and immature percentages for fall dif- fered from 1969-1973 and 1974-1978, but sample size was small (Table 4). The smallest males are about two-thirds the size of the largest females (Godfrey 1966). However, I was unable to determine the sex of 54% of sight- ings. Under some conditions, especially when flying falcons interacted with other birds, their relative size could be assessed with confidence. Large peregrines outnumbered small ones by a factor of 3:1 in the adults and 9:1 in immatures. Although females outnumbered males also in 1969-1978, values differed substantially, probably reflecting the unreliability of basing sex ratios on sightings. Females outnumbered males by a factor of 3:1 or more in coastal migration surveys (Hunt et al. 1975; Ward and Berry 1972). Behavior - I saw falcons attack prey species 254 94 Dick Dekker Vol. 18, No. 3 Table 1. Days and hours afield, and peregrines sighted, 15 April - 31 May 1969-1983. (figures in brackets represent the main migration period 4-23 May, when respectively 79, 85 and 79% of pooled sightings occurred in 3 groups of 5 years). Year Days Afield Hours Afield Sightings Mean Sightings/Hr 1969 22(12) . 20(9) _ 1970 25(16) - 15(11) - 1971 27(17) - 33(27) - 1972 25(16) - 26(21) - 1973 23(16) - 41(39) - Sub-Totals 122(77) - 135(107) - 1974 26(16) 251(166) 46(43) 0.18(0.26) 1975 29(16) 284(171) 41(35) 0.14(0.20) 1976 30(17) 307(196) 66(53) 0.21(0.27) 1977 38(19) 378(216) 163(153) 0.43(0.71) 1978 34(19) 358(229) 90(64) 0.25(0.28) Sub-Totals 157(87) 1570(978) 406(348) 0.26(0.36) 1979 31(16) 289(179) 57(46) 0.20(0.26) 1980 34(18) 323(194) 94(55) 0.29(0.28) 1981 34(19) 308(193) 67(59) 0.22(0.31) 1982 33(18) 276(172) 58(53) 0.21(0.31) 1983 35(19) 302(197) 63(56) 0.21(0.28) Sub- Totals 167(90) 1498(035) 339(269) 0.23(0.29) times. The success rate of 191 hunting attempts of which the outcome was known was 9.4%, not sig- nificantly different from the 7.7% reported for 1965-1979 (Dekker 1980). Prey captured included 9 ducks of 7 species and 9 shorebirds of 4 species. In the first 2 h after daybreak, when I was rarely in the field (Table 2), I only once saw a falcon attack ducks, but I found falcons feeding on ducks 7 times. In one case the prey was a Gadwall (Anas strepera) I had seen killed by a falcon the previous evening at dusk. In the others, sunken eyes of ducks and amount of meat taken from the carcasses led me to suspect that they had been killed the previous evening, during the night or near dawn. On several occasions I saw peregrines attack ducks 0.5-1 h after sundown, and they hunted sandpipers or pas- serines very late in the evening. Crepuscular foraging activity of peregrines has been reported by several observers (Beebe 1960; Clunie 1976; De- kker 1980). Some falcons that I watched at nightfall stayed on posts until it was too dark to see them and they probably roosted there. Their locations were not only over water but also on open pasture. All roosting falcons (n=9) were gone next morning at dawn. Most resting falcons that I watched in the morn- ing from 1 h after sunrise remained inactive until 0900-1100 H when some began to hunt; others soared to great heights and sailed away in a nor- therly direction, apparently resuming migration. In 1969-1978, falcons under observation left the study area in late morning by soar and sail flight at great altitudes (Dekker 1979). Each spring, 1 or 2 recognizable peregrines stayed in the study area for Fall 1984 Peregrine Falcon Migration 95 Table 2. Percent of total field time for 5 daily periods, 15 April-31 May (figures in brackets represent main migration period 4-23 May). Data pooled for periods of 5 years. Mean sightings per hour afield not available for 1974-1978 when the exact time of most sightings was not recorded. % of Total Hours Afield Mean Sightings/Hr Time Period 1974- 1978 1979- 1983 1979- 1983 0500 - 0900 6.7 (7.7) 8.3 (10.5) 0.28 (0.33) 0900 - 1200 19.3 (21.6) 17.8 (19.1) 0.28(0.36) 1200- 1500 24.8 (24.3) 20.5 (20.5) 0.17 (0.21) 1500- 1800 26.9(24.1) 27.0(23.7) 0.20 (0.26) 1800-2200 22.4 (22.3) 26.4(26.2) 0.24 (0.31) TOTALS 100 (100) 100 (100) 0.23 (0.29) 3-8 d, no doubt causing duplication of sightings. Conclusions - Although mean numbers of sightings/h in spring were 11-19% lower in 1979- 1983 than in the preceding 5 yrs, most yearly figures have remained similar, suggesting that no change has occurred in the size of the spring popu- lation migrating through central Alberta. An ex- ceptional year was 1977 when sightings/h were 65-95% higher than the 5 yr mean (Table 1). The spring of 1977 was characterized by dry climatic conditions when peregrines and their prey con- centrated on the lake shore where they were readily located. Why peregrines were much scarcer in fall than in spring in the study area is not clear. Perhaps some peregrine populations breeding in the northwest migrate in fall via a flight path east of Alberta to the Atlantic coast, but return in spring by a more direct Table 3. Mean early dates, mid-dates (half of total sightings) and mean late dates for adult and immature peregrines sighted during spring migration in central Alberta. Data pooled for 3 groups of 5 years, 1969-1983. (“All sightings” include falcons of unidentified age). Mean Early Dates Mid-Dates Mean Late Dates Years Adult Immatures All Sightings Adult Immatures All Sightings Adult Immatures All Sightings 28 3 29 8 15 13 19 25 25 1969-1973 April May April May May May May May May 25 7 24 7 14 12 19 25 25 1974-1978 April May April May May May May May May 28 4 25 9 16 11 22 24 25 1979-1983 April May April May May May May May May 96 Dick Dekker Vol. 18, No. 3 Table 4. Age composition of peregrines in percent of total sightings during spring and fall. Data pooled for 3 groups of 5 years, 1969-1983. Years Sightings % Adult % Immature % Unidentified Spring 1969-1973 135 38 36 26 1974-1978 406 28 47 25 1979-1983 339 29 32 39 Sub-Totals 880 32 38 30 Fall 1969-1973 10 50 30 20 1974-1978 17 6 65 29 1979-1983 24 21 58 21 Sub-Totals 51 26 51 23 route through the continent. Differentiation of spring and fall migration routes has been documented for some shorebird species (Godfrey 1966). Early and late dates of fall and spring sightings in the study area were respectively 16 and 41 d apart in 1979-1983 and 24 and 45 d in 1969-1978. Why the spring passage lasts so much longer than the fall migration is not known. Perhaps spring migrant peregrines, especially subadults, linger in the study area attracted by the concentrations of migrating shorebirds, which are more numerous in May than at any time during fall. Although the number of fall migrating pereg- rines was too small for comparisons, the number of sightings/d increased from 0.24 in 1969-1978 to 0.30 in 1979-1983, consistent with increases in sightings per unit effort during fall migrations along the Atlantic and Texas coasts (F.P. Ward, pers. comm.). Acknowledgment This study was Financed by the Alberta Fish and Wildlife Divi- sion, the World Wildlife Fund (Canada), and the Alberta Recrea- tion, Parks and Wildlife Foundation. I thank W. Wishart for support. A.J. Erskine, R.W. Nelson and F.P. Ward read the man- uscript. Denise Fitz did the typing. Literature Cited Beebe, F.L. 1960. The marine peregrines of the Northwest Pacific Coast. Condor 62:145-189. Clunie, F. 1976. A Fiji peregrine in an urban environ- ment. Notorms 23:8-28. Dekker, Dick. 1977. Field identification of Peregrines, Prairie Falcons and Gyrs in southern and central Al- berta. Alberta Naturalist 7(1): 1-5. Dekker, Dick. 1979. Characteristics of Peregrine Fal- cons migrating through central Alberta, 1969-1978. Can. Field-Nat. 93:296-302. Dekker, Dick. 1980. Hunting success rates, foraging habits, and prey selection of Peregrine Falcons mig- rating through central Alberta. Can. Field-Nat. 94:371-382. Dekker, Dick. 1982. Occurrence and foraging habits of Prairie Falcons, Falco mexicanus, at Beaverhill Lake, Alberta. Can. Field-Nat. 96:477-478. Dekker, Dick. 1983. Gyrfalcon sightings at Beaverhill Lake and Edmonton, Alberta, 1964-1983. Alberta Naturalist 13(3): 103. Fyfe, R.W., S.A. Temple, and T.J. Cade. 1976. The 1975 North American Peregrine Falcon survey. Can. Field-Nat. 90:228-273. Fall 1984 Peregrine Falcon Migration 97 Godfrey, W.E. 1966. The Birds of Canada. National Museum of Canada Bulletin 203. 428 pp. Hickey, J.J. (Editor). 1969. Peregrine Falcon popula- tions: their biology and decline. University of Wiscon- sin Press, Madison. 596 pp. Hunt, W.G., R.R. Rogers, and D.J. Slowe. 1975. Mig- rations and foraging behaviour of Peregrine Falcons on the Texas coast. Can. Field-Nat. 89:111-123. Ward, F.P. and R.B. Berry. 1972. Autumn migrations of Peregrine Falcons on Assateague Island, 1970- 1971./ of Wild. Mgt. 36:484-492. 3819-112 A Street, Edmonton, Alberta, Canada T6J 1K4. Received 20 November 1983; Accepted 15 April 1984 Biology and Management of Bald Eagles and Ospreys. A proceedings of 32 refereed papers (325 pp.) by over 50 international experts on topics including taxonomy, distribution, winter and breeding population dynamics, nesting habitat and nest site selection, nutritional ecology, prey selection, and management of the North American Bald Eagle and the cosmopolitan Osprey. Typeset and bound with soft cover. To place orders, write to either David M. Bird, Raptor Research Centre, 21,111 Lakeshore Rd., Ste. Anne de Bellevue, Quebec H9X ICO or Dr. Gary Duke, Dept, of Vet. Biol., 295K AnSci/Vet. Med. Bldg., Univ. Minnesota, St. Paul, MN 55108. Price per copy: U.S. $15 plus $2.50 handling; Overseas 15$ (U.S.) plus $5 handling; Canada $18 CDN) plus $3 handling. Send payment with Canadian orders to D.M. Bird and U.S. and overseas orders to the Treasurer, Raptor Research Foundation, Inc. All profits to Raptor Research Foundation, Inc. WINTER HABITAT SELECTION OF DIURNAL RAPTORS IN CENTRAL UTAH David L. Fischer, Kevin L. Ellis and Robert J. Meese ABSTRACT - A total of 525 observations of 10 species was recorded during a winter roadside survey of raptors around Utah Lake, Utah Co., Utah. Six species; Red-tailed Hawk ( Buteojamaicensis ), Rough-legged Hawk (Buteo lagopus), American Kestrel (Falcosparverius), Northern Harrier (Circus cyaneus). Golden Eagle ( Aquila chrysaetos), and Bald Eagle (Haliaeetus leucocephalus)\ accounted for 493 (94%) of the observations. Red-tailed Hawks, Rough-legged Hawks and American Kestrels were found in greater than expected numbers in grassland habitat, Northern Harriers and Golden Eagles in sage/greasewood desert, and Bald Eagles in riparian/lakeshore habitat. Rough-legged Hawks predominantly used utility pole rather than tree perches; American Kestrels predominantly used wire perches; Red-tailed Hawks used tree and pole perches according to availability. All species, except American Kestrels, used areas away from centers of human activity more often than expected. Ornithological literature contains relatively little information on the winter ecology of diurnal rap- tors (Newton 1979). Road surveys taken over sev- eral months can provide information on distribu- tion, relative abundance and habitat use (Craighead and Craighead 1956; Bildstein 1978). This infor- mation may provide a basis for making land use decisions. Although many raptor road surveys have been conducted (Enderson 1965; Johnson and En- derson 1972; Craig 1978; Bauer 1982; Gessaman 1982), few have studied habitat or perch use in relation to availability, a prerequisite for making inferences concerning species preference or selec- tion. Here, we conducted a road survey of winter- ing raptors and sampled the availability of general habitat types, specific perch types and proximity of centers of human activity along a 125 km census route. We then tested the (null) hypothesis that raptor use is in proportion to habitat availability. Where use of a particular habitat type was found to be significantly greater than expected, we infer selection or preference on the part of the species involved. Some argue that selection can only be demonstrated by detailed behavioral observations in which an active choice on the part of the animal is shown (see Morse 1980). We assume, however, that raptors are highly mobile organisms capable of moving from one habitat or perch type to another in a matter of minutes. Therefore, we infer an active choice on the part of the species if it occupies a particular habitat type significantly more often than could be expected by chance. Study Area and Methods A 125 km loop around Utah Lake, beginning near Provo and terminating near Lindon, defined the census route (Fig. 1). Aver- age elevation of Utah Valley is 1371 m. Mean annual precipitation ranges between 30.4 and 40.6 cm. Daily mean temperature during the period December-March ranged from approx. - 15°C to 10°C. Vegetation was a mosaic of agricultural lands (irrigated and dry), Figure 1. Map of census route, Utah County, Utah. sagebrush (Artemesia tridentata) mixed with greasewood (Sarcobatus vermiculatus) desert, grassland/pasture, orchard, and riparian/ lakeside woodland. Topography of the census strip was generally flat. Twelve censuses totalling 42 h were conducted weekly from 8 January to 27 March 1983. Direction of travel along the census route was alternated each week. Roads on the east side of the lake were driven at speeds of 40 kph or less. Those on the west side, where there is little vegetation to impair vision and there are fewer potential raptor perch sites, were driven at speeds of 72 kph or less. Brief stops to identify birds and record data were sometimes made. Mean speed of travel per census was 36 kph. Mean time to complete a census was 3.45 h. The number of observers was usually 2, with 3 observers present on 2 occasions and a single observer present on 1 occasion. Only those birds seen initially with the unaided eye were tallied. Binoculars and a 20x spotting scope were used to aid identifica- tion. For each sighting we recorded location, habitat type, be- havior (flying, perched, hovering, soaring, coursing), perch site and distance from centers of human activity (farmyards, resi- dences, commercial establishments, etc.). Habitat categories used were (1) cultivated farmland, (2) sage (cold desert including some greasewood), (3) grassland (including pasture and grass domi- nated rangeland), (4) riparian (including lakeside woods), (5) or- chard, and (6) residential (including urban and commercial areas and the immediate area around farm and ranch houses). Perch 98 Raptor Research 18(3):98-102 Fall 1984 Winter Habitat Selection in Utah 99 ■ sage EH cultivated B RESIDENTIAL S other gj GRASSLAND H RIPARIAN □ ORCHARD Figure 2. Percent deviation from expected number of raptor sightings by habitat type. categories were (1) utility pole, (2) fence post, (3) wire, (4) tree, (5) shrub and (6) ground. Distance to human activity was recorded as (1) <0.16 km, (2) 0.16 to 0.8 km, or (3) > 0.8 km. Habitat and perch availability were quantified by assuming a census strip width of 1 km (0.5 km each side of road) for that portion of the route on the east side of the lake, and a width of 2 km (1 km each side of road) on the west side of the lake (Fig. 1). These strip widths reflected the maximum lateral distances at which we assumed nearly all raptors present could be spotted with the unaided eye. A random sample of 30, 200-m radius circular plots was taken to estimate the availability of each habitat and perch type within the census strip. Data were analyzed using non-parametric Chi-square methods in which expected values were calculated from the estimates of relative availability of habitat factors. For example, if 25% of the census strip is cultivated farmland, we expect 25% of the sightings of Red-tailed Hawks to be in this habitat. Categories were lumped when expected values were less than 5 (Cochran 1954). Results and Discussion A total of 525 raptor sightings was recorded on 12 censuses. Most frequently observed species with sample size sufficient to analyze were Red-tailed Hawk {Buteo jamaicensis), American Kestrel (. Falco sparverius), Rough-legged Hawk {Buteo lagopus ), Bald Eagle {Haliaeetus leucocephalus ), Northern Harrier ( Circus cyaneus ), and Golden Eagle {Aquila chrysaetos). Species observed in smaller numbers were Prairie Falcon {Falco mexicanus), Merlin {Falco columbarius), Ferruginous Hawk {Buteo regalis) and Cooper’s Hawk {Accipiter cooperii ). Habitat Use - Red-tailed Hawks were not ran- domly distributed among the 6 habitat types (P<0.01). (Fig. 2). The observed number of birds in sage/ grease wood desert was approximately a third of that expected, while the number found in grass- land habitat was over twice that expected. Rough-legged Hawks were also not randomly distributed among habitat types (P<0.1). They were found at approximately the expected fre- quency in sage, more often than expected in grass- lands and far less often than expected in developed areas (residential, etc.) (Fig. 2). This species breeds in remote, nearly treeless areas of the far north (Brown and Amadon 1968). Consequently it is not surprising that it prefers open habitat and shuns areas of intensive human activity. Kestrels were also distributed non-randomly among habitat types (P<0.01). They were found 100 Fischer, Ellis, Meese Vol. 18, No. 3 Figure 3. Percent deviation from expected number of raptor sightings by perch type. twice as often in grassland as expected, but only one-third as often as expected in sagebrush (Fig. 2). Of 4 habitat categories that could be considered (riparian, residential and orchard habitats lumped due to low expected numbers), Northern Harriers and Golden Eagles occurred more frequently than expected in sagebrush and less frequently than ex- pected in all other habitats (Fig. 2). Bald Eagles showed the most restricted habitat use pattern (Fig. 2). They were observed almost exclusively along the west shoreline of Utah Lake, and only where open water was nearby. Though the affinity of wintering Bald Eagles for open water is well documented (Fawks 1960; Southern 1963; Steenhof et al. 1980), most wintering Bald Eagles in Utah occur in sagebrush dominated desert valleys and subsist largely on carrion (Edwards 1969; Platt 1976). The narrow habitat choice found in this study is atypical of the normal habitat use pattern of the species in Utah. Rough-legged Hawks, harriers, kestrels and, to a lesser extent, Red-tailed Hawks are known to prey heavily on cricetine and microtine rodents (Craighead and Craighead 1956). Only Northern Harriers occurred in expected or greater than ex- pected numbers in the sagebrush habitat. The other species used grasslands more often than ex- pected. Though we attempted no investigation of abundance and distribution of prey species, a pre- vious study in central Utah reported similar num- bers of rodents in sage-greasewood as in grassland habitat (Woodbury 1955). Thus, it appears the prey base of the grassland habitat supports more species and greater numbers of wintering raptors than does the prey base of the sagebrush desert. This may be due to greater vulnerability of prey to pre- dation by diurnal raptors in grasslands than in the sagebrush. Furthermore, in the desert, where ele- vated perches are scarce, the aerial foraging of har- riers may be more efficient than the perch and hover hunting strategies employed by Rough- legged Hawks and kestrels. Perch Use - Raptor perches were primarily (83%) in trees or on utility poles. Rough-legged Hawks used poles more than expected (B<.01) whereas Red-tailed Hawks used tree and pole perches roughly according to their availability (Fig. 3). Schnell (1968) and Weller (1964) reported that Rough-legged Hawks tend to perch on poles and lone trees, while Red-tailed Hawks tend to select ■ pole ^TREE □ wire + 100 -] + 75- + 50- + 26- 0 - — -25- -50- -75- - 100 - ¥ 1 RED-TAILED HAWK ROUGH-LEGGED HAWK AMERICAN KESTREL N = 1 37 N=65 N = 74 Figure 4. Percent deviation from expected number of raptor sightings by distance from centers of human activity. Fall 1984 Winter Habitat Selection in Utah 101 perches in groves of trees and along wood edges. Wires, a frequent (77% of total) perch of kestrels, were crudely quantified as being equal in availabil- ity to poles. Although the number of potential perch sites along an interpole length of wire is far greater than on a single pole top (or cross arm), we assume that the choice facing an individual kestrel is essentially a dichotomous one — pole or wire? Kestrels used wire perches more and poles and trees less frequently than expected (PC.01, Fig. 3). Bildstein (1978) also reported a preference of kes- trels for wire perches. Sixty-five of 66 perched Bald Eagles were in trees. Too few sightings of perched Golden Eagles and Northern Harriers were recorded to permit a statistical analysis of perch site preference. Human Disturbance - Red-tailed and Rough- legged Hawks used undeveloped areas more than developed areas (P<0.01, Fig. 4). Over twice as many Red-tailed Hawks were seen more than 0.8 km from human disturbance as would have been expected by chance alone. Only 12 of 79 (15%) observations of Rough-legged Hawks were within 0.8 km of human habitation. Interestingly, slightly more Red-tailed Hawks than expected were re- corded within 0. 16 km of centers of human activity. Large trees were often present around farmyards and ranch houses, whereas trees were often lacking nearby. The greater than expected number of Red-tailed Hawk sightings close to potential human disturbance may be due to a greater availability of perches. Rough-legged Hawks appeared not to use trees as readily as pole perches, and thus, did not perch as often as expected near centers of human activity. Alternatively, Rough-legged Hawks may be less tolerant of human disturbance than are Red-tailed Hawks, and the Rough-legged Hawk’s use of poles may be due, at least in part, to the proximity of a large proportion of the study area’s trees to human activity. American Kestrels were distributed non-ran- domly also(P <0.01). Almost twice as many kestrels were seen < 0. 16 km from human activity as were expected (Fig. 4). Bildstein (1978) found that kes- trels used areas nearer centers of human activity than did other raptors wintering in Ohio. Northern Harriers, Golden and Bald Eagles were seen almost exclusively in undeveloped areas. Therefore, no statistical analysis of this trend was performed. These species seem to avoid developed habitat. Acknowledgments We thank our wives, Darlene Fischer and Barbara Ellis, who either spent weekends looking for hawks or spent them alone. Chris Ellis and Pam Thompson assisted on the censuses. Michael Kochert and Clayton White provided editorial comments which greatly improved this manuscript, Literature Cited Bauer, E.N. Winter roadside raptor survey in El Paso County, Colorado, 1962-1979. Raptor Res. 16:10-13. Bildstein, K.L. 1978. Behavioral ecology of Red-Tailed Hawks, Rough-legged Hawks, Northern Harriers, American Kestrels and other raptorial birds wintering in south central Ohio. Ph.D. Dissertation. Ohio State Univ., Columbus. Brown, L. and D. Amadon. 1968. Eagles, hawks and falcons of the world. McGraw-Hill, New York. Cochran, W.G. 1954. Some methods for strengthening the common chi-square test. Biometrics 10:417-451. Craig, T.H. 1978. A car survey of raptors in southeast- ern Idaho 1974-1976. Raptor Res. 12:40-45. Craighead, J.J. and F.C. Craighead. 1956. Hawks, owls and wildlife. Stackpole Company. Harrisburg, Pennsylvania. Edwards, C.C. 1969. Winter behavior and population dynamics of American Eagles in western Utah. Ph.D. Dissertation, Brigham Young University, Provo, Utah. Enderson, J.H. 1965. Roadside raptor count in Col- orado. Wibon Bull 77:82-83. Fawks, E. 1960. A survey of wintering Bald Eagles. Iowa Bird Life 30:56-58. Gessaman, J.A. 1982. A survey of raptors in northern Utah, 1976-79. Raptor Res. 16:4-10. Johnson, D. and J.H. Enderson. 1972. Roadside raptor census in Colorado - winter 1971-72. Wibon Bull. 84:489-490. Morse, D.H. 1980. Behavioral mechanisms in ecology. Harvard University Press, Cambridge, Massachusetts. Newton, I. 1979. Population ecology of raptors. Buteo Books, Vermillion, South Dakota. Platt, J.B. 1976. Bald Eagles wintering in a Utah de- sert. Amer. Birds 30:783-788. Schnell, G.D. 1968. Differential habitat utilization by wintering Rough-legged and Red-tailed Hawks. Con- dor 70:373-377. Southern, W.E. 1963. Winter populations, behavior and season dispersal of Bald Eagles in northwestern Illinois. Wibon Bull. 75:42-55. Steenhof, K., S.S. Berlinger and L.H. Fred- rickson. 1980. Habitat use by wintering Bald Eagles in South Dakota./. Wildl. Man. 44:798-805. Weller, M. W. 1964. Habitat utilization of two species of buteos wintering in central Iowa. Iowa Bird Life 34:58-62. Woodbury, L. 1955. An ecological and distributional study of small mammals in Cedar Valley, Utah County, 102 Fischer, Ellis, Meese Vol. 18, No. 3 Utah. M.S. Thesis, Brigham Young University, Provo, Utah. Department of Zoology, Brigham Young University, Provo, Utah 84602. Current address second author: Colorado Di- vision of Wildlife, 6060 Broadway, Denver, Col- orado 80216. Current address third author: Department of Wildlife and Fisheries Biology, University of California, Davis, California 95616. Received 3 February 1984; Accepted 1 July 1984 Request for Information Information is being gathered on the post-release behavior and survival of captive-reared and rehabilitated birds and mammals. The objectives of this study are to assess the amount and type of work that has already been done, to summarize the available data and evaluate techniques, and define the reasons for the survival or mortality of released animals. Published and unpublished reports and raw data would be appreciated. For additional information, individuals willing to cooperate please contact Daniel R. Ludwig, Ph.D., Willowbrook Wildlife Haven, Forest Preserve District of DuPage County, P.O. Box 2339, Glen Ellyn, IL 60138. Raptor Collisions with Utility Lines — A Call for Information — The U.S. Bureau of Land Management, Sacramento, in cooperation with the Pacific Gas and Electric Company, is assembling all available published and unpublished information concerning collisions of raptors with power lines and other utility lines. Actual case histories — no matter how circumstantial or fragmentary — are needed. Please acknowledge that you have such information by writing to Dr. Richard R. (Butch) Olendorff, U.S. Bureau of Land Management, 2800 Cottage Way, Sacramento, California 95825 U.S. A. (Phone (916) 484-4541). A form on which to record your information will then be sent by return mail. DO NORTHERN HARRIERS LAY REPLACEMENT CLUTCHES? Robert Edward Simmons Abstract - An ecological difference between North American and European populations of Circus cyaneus is the apparent lack of replacement clutches laid by the North American form (the Northern Harrier) on the failure of the first clutch. I present several lines of evidence that Northern Harriers do lay replacements, but only if their clutches are disturbed during laying or shortly thereafter. Two of the five females that renested were successful in their attempts and the quality of the new nest sites was higher, despite most renests being within 200 m of the old sites. In 2 detailed and long term ( > 20 y) studies of Circus cyaneus, one in Orkney, Scotland (where it is called the Hen Harrier), and one in Wisconsin, U.S.A., a major ecological difference is evident. Harriers in Scotland may lay 1 and occasionally 2 replacement clutches following the failure of their original clutch (Balfour 1957), while harriers in Wisconsin have never been recorded as laying a replacement (Hamerstrom 1969, pers. comm. 1981; Schmutz and Schmutz 1975). Since Simmons and P.E. Barnard (MS) found few behavioural dif- ferences in a comparison of the 2 continents’ populations, other than migratory habits, then this apparent difference warrants attention and expla- nation. Here, I present evidence that harriers in a large Canadian population laid replacement clutches in all 3 y in which they were studied, and that renest- ing females picked higher quality sites for their second attempts. Study Site and Methods One of North America’s largest assemblages of breeding har- riers was studied on the 60 km 2 Tantramar Marsh (45°53'N, 64°20'W), New Brunswick. The objectives were to document breeding and feeding ecology of the population in relation to polygyny. In so doing, the location of each nest was mapped and its history detailed; the date of settling, habitat type, courtship dis- plays, clutch size, and male and female activity (see Simmons 1983 for details). About 2500 h of observation were made, of which 562 h were specific nest watches to record feeding rates. As no birds were marked, the evidence presented here consists of the followng categories: (a) recognition of plumage charac- teristics and voice; (b) identical reaction to human disturbance at both nests, which varied significantly among females; (c) short relaying period; (d) lack of “sky dancing” (Hamerstrom 1969) from any male involved following nest predation; (e) close proximity of nest and renest; and (f) alarm -calling at the nest up to 2 d after nest failure. To determine nest site quality, I recorded dominant vegetation, moisture level, and visibility at each of 64 nests found. Moisture was ranked as Dry if no water existed within 1 m of the nest, Wet if water appeared due to my weight, and Very Wet if water was already present at the site. Vegetation was ranked as cattail ( Typha spp.), marsh grasses (Spartina pectinata or Calamagrostis canadensis), Spirea ( Spirea latifolia and other low shrubs), and alder ( Alnus spp. and willow Salix spp.). Visibility, which was later found to have no effect on the success or failure of each nest (Simmons and Smith 1985), is disregarded here since it does not affect quality. Quality reflects the probability of success, and the quality score for each nest site is a combination of the percentage success of moisture and vegetation categories arcsine transformed, and summed (see Simmons and Smith 1985). Results and Discussion Suspected renesting occurred twice among 30 nests in 1980, and in 3 of 22 nests in 1981. The original nest of a suspected renest in 1982 was not found, and details of 2 renests in 1983 (R.B. MacWhirter and G.L. Hansen in litt.) were not taken, and are not discussed further here. In the first case in 1980, a yellow-eyed female distinguished by a very dark terminal tail band had just completed a clutch of 5 eggs (determined by egg colour: Sealy 1967; Hamerstrom 1969, pers. obs.) in Cattails. She reacted to me by flying 300-400 m east and circled at low altitude while alarm calling. On my next visit, a bird already 300-400 m east of me started cackling. Later, the same bird flew to the new nest and was recognized by her eye and rectrix colour. The fact that she alarm-called near her new nest on my first visit would have been unusual for any other harrier with no prior experience of my activities. In my experience at 59 other first nests, a female never called until I was closer than approximately 80 m on my first visit. The second nest-renest evidence in 1980 (“Alders”: Table 1) consisted of (a) close circling and calling but ho stooping by the female, (b) a 7-d relaying interval, (c) a lack of sky dancing by her polygynous mate who otherwise performed a greater number of displays than any other male (Simmons 1983), and (d) a renest only 160 m from the original site. She was 1 of 2 polygynous females (Table 1) who relaid with the same male (polygynous males were identified by watching them feed one, then another female in succession). In 1981 , in an effort to gain accurate data on egg laying and incubation periods, I disturbed several females with 0- or 1-egg clutches. Five of 6 females 103 Raptor Research 18(3): 103-106 104 Robert Edward Simmons Vol. 18, No. 3 Table 1. Factors associated with 5 renests located on the Tantramar Marsh of New Brunswick, 1980-1981. Renesting Factors* Nest I II III IV V a VI b VII Midgic 1 8 320 9 May 1980 Renest 27 May 1980 Alders y Renest 7 160 18 May 1980 31 May 1980 Midgic 2 Renest 11 100 14 May 1981 25 May 1981 Alders /3 Renest 4 120 14 May 1981 18 May 1981 Phoebe Renest 7 200 1 June 1981 8 June 1981 Just completed 5 144 clutch 5 140 S Egg-laying 4 117 4 114 F° First egg 1 92 2 133 S First Egg 1 92 5 118 F d First egg 1 140 4 140 pe * — I = days between failure and relaying; II = proximity of nests (m); III = clutch initiation dates; IV = stage at failure; V = clutch size; VI = quality score of nest site; VII = outcome of renest attempt: S = successful, F = failed. a All renest clutches were full clutches and hatched. b Based on moisture and vegetation at the nest site (see text); range of scores 92-144. c Diseased chicks ^Observer induced e Predation deserted, and 2 of 5 relaid. A third female, whose 1-egg clutch was taken by a lone Common Raven (i Corvus corax), also relaid. In each case, a renest was established using 2 or more of the categories out- lined in Methods. One /3 female continued to de- fend her destroyed renest for 2 d following its de- struction. This is in contrast to evidence presented by Hamerstrom (1969) for Wisconsin harriers which left the area within 24 h of nest loss, and indicates the potential for a female to remain and renest on the Tantramar Marsh. Three characteristics common to all 5 renesters emerge from their histories: (1) all failed while in the process of egg-laying or shortly thereafter; (2) the distance between the nests was, in 4 of 5 cases, closer than the minimum distance recorded bet- ween concurrently occupied nests (260 m); and (3) the period between failure and relaying was short, averaging 7.4 (± 3) d. Morrison and Walton (1980), in their review of replacement clutches in raptors, reported that the frequency of relaying was greater among birds whose clutches were disturbed early in thd breeding attempt, and that renesting generally took place within “several hundred metres”. These facts concur with (1) and (2) in this study. The significance of the short relaying period (3) can be seen in light of the fact that on the Tantramar Marsh, females settling into new territories (i.e. courting and preparing to lay eggs) required at least 1 wk and usually longer (Simmons 1983) to put on sufficient fat/protein reserves (cf. Newton et al. 1983, Hirons et al. 1984) before laying their first egg. Since the average relaying interval was only 1 wk for renesters, this implies that a female part way through laying finds it easier to begin a new clutch, having not fully depleted her protein reserves, than a female starting afresh. This may explain the short relaying interval (Table 1). It is also significant in this regard that the female with the longest relaying interval (Midgic 2) also produced the smallest re- peat clutch (Table 1), and was fed very little by her monogamous mate (Simmons 1983). A related but paradoxical fact arises from a comparison of relaying intervals reported for other Fall 1984 Northern Harrier Replacement Clutches 105 small falconiforms (12-18 d : Morrison and Walton 1980) and those found in this study (7.4 d). This difference may be related to the fact that many of the falcons and accipiters cited (ibid.) were deliberately double-clutched and therefore “failed” after producing a full clutch, while the harriers failed earlier in their attempts. The relaying intervals (Table 1) concur with those found by Balfour (1957) who stated that replacements were often completed within a fortnight by Hen Harriers in Orkney. The frequency of renesting (8 nests in 96: 8% [Simmons 1983, 1983a; G.L. Hansen and R.B. MacWhirter in litt.]) over 4 y on the Tantramar Marsh is also similar to that found in Orkney (N. Picozzi, pers. comm.). Newton (1979:136) argued that the proportion of relaying raptors in A population is determined by food supply; evidence from this study does not support this hypothesis. Microtines and shrews (Sorex spp.), principal prey of the harriers on the Tantramar Marsh (Barnard 1983), were sampled each year (ibid, and G.L. Hansen in litt.) and related to the proportion of renesters. Spring vole abundance could be ranked from highs in 1980 and 1983 to lows in 1981 and 1982, yet renests accounted for 6.3%, 6.6%, 13.6% and 8.3% of all nests in these years respectively. Several factors (other than my research activities) therefore must have been operating over and above food abundance to produce these results. Further evidence which does not support the food-related hypothesis comes from a survey of other records of renesting among Northern Harriers. Riendahl( 1941) reported 1 nest among 5; Craighead and Craighead (1956) reported 1 renest among 9 in a year of low vole abundance, but none in a “high” year; Smith (1971) recorded 1 among 5 nests, and Duebbert and Lokemoen (1977) reported 1 among 3 nests. If low numbers of nests were indicative of a low vole population (cf. Hamerstrom 1979; Simmons et al. in prep.) in these studies, then none of them support the food-related renesting hypothesis (Newton 1979). If nests are destroyed by predators, it is surprising that the harriers studied generally renested within 200 m of their original sites; their mates often held territories up to 1 km in diameter (Simmons 1983), and suitable nesting substrate appeared to be relatively unlimited. This unusual situation was investigated through an estimation of the quality of the nest and renest in terms of anti-predator adaptations. This was based on the knowledge that Very Wet cattail sites were significantly more successful than most other combinations (Simmons and Smith 1985). The results indicate that harriers could afford to locate their renests close to their original nests, since on average they chose better quality sites. Four of the 5 renests stayed in high quality sites or increased in quality, while overall the quality scores increased by an average of 12 points; this was not significant, however (Wilcoxson test, U = 10, P = 0.3). Even so, all 5 renesters hatched eggs; 2 raised flying young and only 1 renest failed again due to predation. I conclude that North American harriers do lay replacement clutches if their origihal clutch fails early in the attempt, at about the same frequency as their European conspecifics. As the Northern Harrier is behaviourally very similar to the Hen Harrier, the fact that they both lay replacement clutches adds to the contention that they are also ecologically very similar. Acknowledgments This study was made possible through 2 graduate fellowships from Acadia University and financial support through my supervisor Dr. P.C. Smith. I thank P.E. Barnard and the Canadian Wildlife Service, Sackville, New Brunswick, for their assistance, and Frances Hamerstrom and Nick Picozzi for their interesting discussions. Mark Fuller helped clarify the paper through constructive criticism, and Bruce MacWhirter and Gay Hansen kindly supplied unpublished material. Literature Cited Balfour, E. 1957. Observations on the breeding biology of the Hen Harrier in Orkney. Bird Notes 27:177-183. Barnard, P.E. 1983. Foraging behaviour and energetics of breeding Northern Harriers Circus cyaneus (L.) B.Sc. (Hons) thesis, Acadia Univ., Nova Scotia. Craighed, J.J. and F.C. Craighead. 1956. Hawks, owls and wildlife. Dover Publ. Inc., New York. Duebbert, H.F. and J.T. Lokemoen. 1977. Upland nesting of American Bittern, Marsh Hawk and Short-eared Owl. Prairie Nat. 9:33-40. Hamerstrom, F. 1969. A harrier population study. Pp. 367-385 in: J.J. Hickey (ed.) Peregrine Falcon populations: their biology and decline. Univ. of Wisconsin Press, Milwaukee. Hamerstrom, F. 1979. Effect of prey on predator: voles and harriers. Auk 96:370-374. Hirons, G.J.M., A.R. Hardy, and P.I. Stanley. 1984. Body weight, gonadal development and moult in the Tawny Owl (Strix aluco).J. Zool., Lond. 202:145-164. Morrison, M.L. and B .J. Walton. 1980. The laying of 106 Robert Edward Simmons Vol. 11, No. 3 replacement clutches by Falconiformes and Strigiformes in North America. Raptor Res. 14:79-85. Newton, I. 1979. Population Ecology of Raptors. T. and A.D. Poyser, Berkhamsted, Hertfordshire, England. Newton, I., M. Marquiss, and A. Village. 1983. Weights, breeding and survival in European Sparrowhawks. Auk 100:344-354. Riendahl, E. 1941. A story of Marsh Hawks. Nature Mag. April: 191-194. Schmutz, J.K. and S.M. Schmutz. 1975. Primary molt in Circus cyaneus in relation to nest brood events. Auk 92:105-110. Sealy, S.G. 1967. Notes on the breeding biology of the Marsh Hawk in Alberta and Saskatchewan. Blue Jay 25:63-69. Simmons, R.E. 1983. Polygyny, ecology and mate choice in the Northern Harrier Circus cyaneus (L.). M.Sc. thesis, Acadia University, Nova Scotia. Simmons, R.E. 1983a. The harriers of the Tantramar. New Brunswick Nat. 12:9-12. Simmons, R.E. and P.C. Smith. 1985. Do Northern Harriers Circus cyaneus choose nest sites adaptively? Can. J. Zool. (in press). Smith, D.G. 1971. Population dynamics, habitat selection and partitioning of the breeding raptors in the Eastern Great Basin of Utah. Ph.D. thesis, Brigham Young Univ. Utah. Department of Biology, Acadia Univ., Wolfville, Nova Scotia BOP IXO. Present address: Department of Zoology, Univ. of Witwatersand, Johannesburg, South Africa. Received 27 December 1983; Accepted 1 August 1984 UNUSUAL PREDATORY AND CACHING BEHAVIOR OF AMERICAN KESTRELS IN CENTRAL MISSOURI Brian Toland Abstract - Caching behavior of the American Kestrel (Falco sparverius) was studied 1981-1983 in Boone County, Missouri. Both wild prey and quarry thrown from car windows were cached. Kestrels cached food 116 times and retrieved it 77.5% of the time. Males cached food in elevated sites (at least 4 m high) 64% of the time while females did so only 20%. During spring and summer, 93% of the prey items were cached uneaten. During fall and winter, only 42% of the food cached was uneaten. When a surplus of prey was created by releasing several mice at a time, kestrels killed them while flying to their cache sites. These prey items were stored in the same cache site. Apparently, caching behavior of American Kestrels is not directly correlated with the length of time between feedings, and caching behavior operates independently of food deprivation, especially in spring and summer. Many reptors have been observed caching prey. Mueller (1974) provided a review of food storing in several captive species. Among the falconiforms, prey caching seems to be most developed and wide- spread in falcons. Published records of caching in- clude those for the Merlin ( Falco columbarius) (Greaves 1968; Oliphant and Thompson 1976; Pitcher et al. 1982), American Kestrel ( F . sparverius ) (Pierce 1937; Tordoff 1955; Roest 1957; Stendell and Waian 1968; Balgooyen 1976; Collopy 1977), Prairie Falcon (F. mexicanus ) (Peterson and Sitter 1975; Oliphant and Thompson 1976), Peregrine Falcon ( F . peregrinus) (Beebe 1960; Brown and Amadon 1968; Nelson 1970; Cade 1982), Gryfal- con (F. rusticolus) (Jenkins 1978; Cade 1982) and many others. Study Area and Methods Data reported here are from a 48 km 2 area in Boone County, Missouri, where farmlands are interspersed with woodlots, old Fields, meadows and residential areas. I observed kestrels from September 1981 through August 1983 using a 30x spotting scope and 9x binoculars at distances of 5-200 m. For each observation I recorded species cached, location of cache, weather conditions, time of day, and duration of caching sequence. Additional live prey was thrown from my car window to kestrels perched within 25 m of roads. The prey thrown were brown, gray, white and black House Mouse (Mas musculus) and House Sparrows (Passer domestkus) with several primaries pulled to ensure their capture by kestrels. Results and Discussion During the 2 yr study 1210 h of observation of kestrels were made and 30 kestrels were seen cach- ing prey a total of 116 times. They subsequently retrieved food successfully 77.5% of the time. Prey cached were 95% rodents and 5% birds. Both wild and provided prey were cached. Kestrels captured 95% of the prey thrown from car windows and cached 46 (48%). The remaining 70 (60%) prey cached consisted of 55 Prairie Vole ( Microtus oc- hrogaster ), 6 house mice, 3 White-footed Mouse (Peromyscus leucopus) 2 Western Harvest Mouse ( Reithrodontomys megalotis), 2 House Sparrows, 1 Grasshopper Sparrow (Ammodramus savannarum) and 1 Eastern Meadowlark ( Stumella magna). Cache sites were of 8 kinds (Table 1). Males cached prey in elevated sites significantly more Table 1. Cache sites used by American Kestrels in Boone County, Missouri 1981-83. Location and Height of Caches Sex Grass clumps (0-0.1 m) Hollow railroad ties (0-0.1 m) Tree roots (0-0.1 m) Bushes (0. 5-1.0 m) Fence Building posts gutters (1.0 m) (4.0 m) Tree limbs and holes ( 4.5 m) Tops of power poles (10.0-20.0 m) Total M 16 3 1 1 6 2 44 3 76 F 27 0 0 2 3 0 8 0 40 107 Raptor Research 18(3): 107-1 10 108 Brian Toland Vol. 18, No. 3 often than did females (Table 1). Males cached prey 4 m or more above the ground 64% of the time, while females did so only 20% (X 2 = 22.16, P<0.01, df=l). During the breeding season kestrels have special courtship feeding ceremonies (Fox 1979; Cade 1982). Food transfer often begins as remote food passing (Nelson 1977) when the male deliberately caches prey within view of the female. When he leaves, she flies to the cache, retrieves and eats the food. I observed that all copulation and courtship activities including hitched wing-displays, food begging, courtship feeding and remote food pas- sing occurred at elevated sites, on or near favorite -plucking or hunting perches. Because males alone cache prey at these elevated sites during courtship they may be predisposed to cache in elevated sites during the rest of the year. Partially eaten carcasses were always decapitated before being cached and only the posterior 2/3 to 1/2 of the body of the prey was placed in the cache. However, kestrels cached 78% (36 of 46) of the presented prey and 69% (48 of 70) of wild prey completely uneaten. Of all prey items cached, only28% (32 of 116) were decapitated. In contrast Stendell and Waian (1968) reported that 14 of 15 small mammals cached by a single female kestrel were decapitated and Collopy (1977) reported that 10 female kestrels decapitated 13 of 17 (76.5%) small animals cached. In Missouri kestrels cached more (58%, 27 of 48) partly-eaten prey during the fall and winter than the 7% (5 of 68) during spring and summer, which may be explained by the lack of hunger during the breeding season due to greater availability of food and warmer temperatures. Kestrels hiding food approached the cache site furtively, then thrust, pushed, or nudged the prey into position with the beak (see Balgooyen 1976; Collopy 1977). Sometimes sites apparently were selected before the flight started, and kestrels flew directly to the cache spot. Prey was not placed in any preferential position such as belly-down (as if to take advantage of the prey’s protective coloration) as reported by Balgooyen (1976) and Collopy (1977). I found items lying on back or sides as often as on the belly. Kestrels sometimes did make several attempts at repositioning prey until it was better concealed. In all cases when prey was stored on the ground in grass clumps, kestrels chose sites next to fence posts, utility poles, sign posts, or other mar- kers. Tordoff (1955) observed that a captive kestrel which cached prey used objects nearby to memorize the location of the cache site. When retrieving prey, kestrels flew to the cache site and if unable to find stored prey, hovered above the area or walked to adjacent grass clumps to search. In several instances kestrels appeared to give up their search when they flew to a nearby perch, only to return and resume the search. One female kestrel spent 15 min investigating grass clumps both on foot and in brief hovers before giving up. Because my field observations were evenly distri- buted throughout the day, I assumed that there was no difference in the probability of observing either prey storing or retrieval (see Collopy 1977). On this assumption, I considered my caching data as a rep- resentative sample of the relative frequency of prey caching and retrieving and calculated a recovery efficiency of about 78%, similar to the 70% re- ported by Collopy (1977). 1 observed that presenting kestrels with live prey stimulated a response that simulates the reactions of kestrels to natural prey. The typical response was to fly from the perch toward the prey within 20 sec of its detection. Kestrels then would either (1) bind to the quarry on the ground and kill it with a bite to the neck immediately (or after having flown to a nearby perch) or, (2) snatch the prey from the ground without landing and fly to a nearby perch to dispatch it with a bite to the neck. On 6 March 1982 at 1430H I observed a female through binoculars from a distance of 100 m. The weather was 38°C, calm and clear. I approached in my car to within 25 m, threw a white mouse out the window and waited. Within 2 min the kestrel ap- proached within 4 m of my car, hovered, and then retreated to a wire 20 m away. I then threw out 2 more mice and backed the car 25 m away. At 1440 H the kestrel again flew toward the mice but after hovering above them and looking at my car, again retreated to the wire only 15 m distance. I then presented 4 more white mice for a total of 7, all of which were conspicuous against a recently mowed lawn. At 1445 Hthe kestrel flew to a wire only 5 m from the mice and after hesitating for 15 or 20 sec flew down and captured a mouse. However, she immediately flew west 75 m during which flight I saw her bend over several times in midair to bite the neck of the mouse. She immediately landed on the ground and cached the prey in a grass clump at the base of a fence post. She quickly returned to cap- Fall 1984 American Kestrel Caching Behavior 109 ture and dispatch in flight the remaining mice in rapid succession. All 7 mice were cached in 1 or 2 grass clumps 1 m apart. None of the 7 mice were eaten at this time. A month later at the same time of day a male took 7 mice in the same fashion, killing them midair as it flew to the cache site in a white oak tree ( Quercus alba). I was able to elicit the capture and caching of as many as 10 mice in sequence by both captive and wild kestrels when presenting them with prey one at a time, over 2 to 8 h periods. Nunn et al. (1976) reported that 1 wild female took 20 white mice thrown from a car window one at a time, over an hour. I found no literature reports of American Kestrels responding to a sudden increase in prey availability by mid-flight killing and caching of suc- cessive prey items uneaten. Caching has been described as a behavorial mechanism to exploit a seasonal or daily abundance of prey, thereby maximizing food intake and dam- pening the effects of fluctuations in prey availability (Balgooyen 1976; Collopy 1977). My studies agree with other researchers that kestrels, like other fal- cons, store extra food for periods of a few hours to several days, especially when the capture of suffi- cient prey may be difficult (i.e., inclement weather, snow cover, or brood rearing). Although winter food storing in kestrels may be stimulated by a “hunger drive” (see Mueller 1973, 1974) in part, my observations agree with Collopy (1977), Fox (1979) and Cade (1982) that Lorenz’ (1937) model of instinctive behavior operating in- dependently of food deprivation occurs in kestrels during the nesting season. Mueller’s (1973) laboratory findings, in which the predatory be- havior of kestrels was directly correlated with length of time between feedings, was not substan- tiated. Fifty-eight percent of the prey cached in fall and winter was partially eaten, but only 7% during the nesting season. This indicates that hunger drive does not explain caching behavior of courting males or parental food storing behavior during nesting. When presented with a surplus of easily captured prey (both in late winter and spring) kestrels killed prey as they flew to a cache site, thus expediting capture of an ephemeral abundance of prey. The accompanying caching of multiple prey items in the same cache or nearby appears to be yet another example of the flexible behavior of kestrels attempting to hurriedly exploit sudden surpluses in prey availability. Because I saw kestrels caching 7 prey items together in a 5-min period, I cannot support Mueller’s (1973) statement that “excessive killing resulted from the falcon “forgetting” that it had cached food when it was exposed to the prey stimulus.” Kestrels cache several consecutive prey items in the same spot in a period of minutes or days, and later retrieve them (Stendell and Waian 1968). Acknowledgments I appreciate the guidance of William H. Elder. Tim Haithcoat and Dave Scarbrough provided valuable field assistance. Thomas S. Baskett and Curtice Griffin provided constructive criticism of the manuscript. The Natural History Section of the Missouri De- partment of Conservation funded this study, and the Missouri Cooperative Wildlife Research Unit (U.S. Fish and Wildlife Ser- vice, Missouri Department of Conservation, Wildlife Management Institute, and School of Forestry, Fisheries and Wildlife, Univer- sity of Missouri-Columbia, cooperating paid publication costs. Literature Cited Balgooyen, T.G. 1976. Behavior and ecology of the American Kestrel in the Sierra Nevada of California Univ. California Publ. Zool. 103:1-83. Beebe, F.L. 1960. The marine Peregrines of the nor- thwest Pacific coast. Condor 62:145-189. Brown, L.H. and D. Amadon. 1968. Eagles, hawks and falcons of the world. McGraw-Hill, New York. Cade, T.J. 1982. The falcons of the world. Cornell Univ. Press, Ithaca, New York. Collopy, M.W. 1977. Food caching by female American Kestrels in winter. Condor 79:63-68. Fox, N. 1979. Nest robbing and food storing by New Zealand Falcons. Raptor Res. 13:51-56. Greaves, J.W. 1968. Food concealment by Merlins. British Birds 61:310-311. Lorenz, K. 1937. Uber die Bildung des Instinkt begrif- fes. Die naturwissenschaften, 25, Heft 19. (as found in studies in animal and human behavior, Vol. I, pp. 259-312. Translated by Robert Martin, Cambridge, Mass., Harvard Univ. Press). Mueller, H.C. 1973. The relationship of hunger to predatory behavior in hawks {Falco sparverius and B ute o platypterus). An. Behav. 21:513-520. 1974. Food caching behavior in the American Kestrel. Z. Tierphycol. 34:105-114. Nelson, R.W. 1970. Some aspects of the breeding be- havior of Peregrine Falcons on Langara Island, B.C. MS Thesis, Univ. Calgary, Alberta. 1977. Behavioral ecology of Coastal Peregrines (Falco peregrinus pealei). Ph.D. Dissertation, Univ. Calgary, Alberta. Nunn, G.L., P, Klem, Jr., T. Kimmel and T. Merri- man. 1976. Surplus killing and caching by American 110 Brian Toland Vol. 18, No. 3 Kestrels. An. Behav. 24:759-763. Oliphant, L.W. and J.P. Thompson. 1976. Food cach- ing behavior in Richardson’s Merlin. Can. Field-Nat. : 364-365. Peterson, S.R. and G.M. Sitter. 1975. Raptor nesting and feeding behavior in the Snake River Birds of Prey Natural Area, Idaho: An Interim Report. Snake River Birds of Prey Research Proj. Ann. Rep. 1975:179-185. Pierce, W.M. 1937. A pet Sparrow Hawk. Condor 39:137-143. Pitcher, E., P. Widener and S.J. Martin. 1982. Winter food caching by the Merlin. Raptor Res. 13:39-40. Roest, A.L. 1957. Notes on the American Sparrow Hawk. Auk 74:1-19. Stendell, R.C. and L. Waian. 1968. Observations of food-caching by an adult female Sparrow Hawk. Con- dor 70:187. Tordoff, H.B. 1955. Food storing in the Sparrow Hawk. Wilson Bull. 67:139-140. Department of Forestry, Fisheries and Wildlife, University of Missouri, Columbia, MO 65201. Received 8 March 1984; Accepted 18 September, 1984. Fall 1984 Short Communications 111 Short Communications 1981 - An Extraordinary Year for Golden Eagle “Triplets” in the Central Rocky Mountains M. Alan Jenkins and Ronald A. Joseph The clutch size of the Golden Eagle (Aquila chrysaetos ) ranges from 1 to 4 eggs with a mean near 2 (Brown 1977). Clutches of 3 are unusual, occurring less than 10% of the time (Table 1). Normally, 1 to 3 young fledge/successful nest with a mean of 1.2 to 1.4 (Brown 1977). Table 1. Frequency of 3-egg clutches in the Golden Eagle. and Collopy 1983). We are unable to assess the influence of these factors on the high number of triplets in 1981 with the possible exception of the influence of high prey densities. Clutch size, and therefore, ultimate productivity (number of fledged young/successful nest), are partly in- Study Area Year(s) No. OF Clutches No. of 3-egg Clutches % of 3-egg Clutches Reference California 21 3 14.3 Slevin, in Arnell 1971 Scotland 82 8 9.8 Gordon 1955 Colorado 5 0 0.0 Jollie, in Arnell 1971 Montana 1963-1964 60 4 6.7 McGahan 1966 Montana 1963-1968 30 1 3.3 Reynolds 1969 Utah 1957-1958 5 0 0.0 Hinman [no date] Utah 1967-1968 23 1 0.4 Murphy et al. 1969 Utah 1969-1970 26 8 30.8 Arnell 1971 Idaho, Oregon 1966 15 1 6.7 Hickman [no date] TOTALS 267 26 MEAN 9.7 Various factors, from failure to lay eggs to mortality of nestlings, reduce the probability of a pair of eagles fledg- ing 3 (“triplets”) from a nest. Table 2 compares data on the frequency of 3 fledgling nests from various studies of Golden Eagles in the western United States. In 1981, we independently surveyed eagle nests for productivity and recorded nests with 3 nestlings. We sub- sequently discovered that other investigators, in Utah especially, found 5 nestling nests. The mean percentage (3.8%) of nests fledging triplets in 1981 in Utah, Col- orado, and Wyoming is significantly higher P < 0.10) than the mean percentage of triplets for other years in the western United States (Table 2). We assumed that mortal- ity of the nearly-grown nestling eagles observed in 1981 was low and that most nearly-grown nestlings fledged. Most studies with which we compared our data also made that assumption by counting nearly-grown nestlings as fledglings. Many factors can influence productivity in Golden Eagles as reviewed by Newton (1979); also see Edwards fluenced by the quantity of food adult females eat before egg-laying affecting her nutritional state of health (New- ton 1979). Newton (1979) pointed out that rodent-eating raptors lay clutches that can vary directly in size with rodent densities in the nest area. This allows raptors to exploit rodent and other cyclic prey species in high density years by increasing productivity. Evidence suggest that this is true of Golden Eagle-prey relationships, because the eagle’s diet in North America is mainly (74%) lagomorphs and rodents (Olendorff 1976) that exhibit cyclic populations (Murphy 1975). This relationship may be moderated by other factors. In the western United States lagomorph populations appear to have increased in the years leading up to 1981. In southwestern Idaho populations of Black- tailed Jack- rabbits ( Leus califomicus ) reached plague proportions in the winter of 1981-82, as reported in the popular press (e.g., Trueblood 1982). Jackrabbit densities were the highest in 9 y in 1981 in the Snake River Canyon of Idaho (Steenhof et al. 1983). In Utah, jackrabbit censuses con- 112 Short Communications Vol. 18, No. 3 Table 2. Frequency of three-fledgling (triplet) Golden Eagle nests in the western U.S. Study Area Year Total No. Successful No. with Throughout Study Triplets % Successful w/Triplets Reference Years Other Than 1981 Idaho, Oregon 1966 17 0 - Hinman* no date Utah 1957-1958 . 5 0 - Hinman, no date Utah 1967-1968 18 0 - Camenzind 1968 Utah 1969-1970 19 3 15.8 Arnell 1971 Wyoming, Colo. 1964-1980 882 1 0.1 Den. Wildl. Res. Ctr. data Wyoming 1979 11 0* - Lockhart et al. 1980 Wyoming, Mont. 1975-1978 34 0* - Lockhart et al. 1978 Montana 1963-1964 55 3 5.5 McGahan 1966 Montana 1962-1968 22 0 - Reynolds 1969 Oklahoma 1974-1975 6 0 - Lish 1965 Texas 1974-1975 5 0 - Lockhart 1976 TOTALS 1,074 7 MEAN 0.7 1981 Data Utah 1981 95 6 6.3 Present study Colorado 1981 94 3 3.2 Pearson, Grode pers. comm. Wyoming 1981 46 0 0 Phillips and Beske 1981 TOTALS 235 9 MEAN 3.8 ♦Data gathered by personal communication with the author. ducted by the Department of the Army (R. LeClerc pers. comm.) showed that densities were high(though decreas- ing thereafter) in autumn 1980 at 3 northwestern Utah study sites, moderate populations at 3 others, and low at 1 Nevada site. Data from both Steenhof et al. (1983) and the Army show similar high densities in 1971 supporting the hypothesis of a 10 yr jackrabbit population cycle in these areas. Increased prey availability for nesting eagles is probably an important cause for higher than normal frequency of triplets in the western United States in 1981. The only other instance of a high frequency of triplets is the study of Arnell (1971) in Utah. He noted hi ah lago morph populations in 1971, 10 yr before the high number of triplets in 1981. Acknowledgment is due to Dugway Proving Grounds (Dept, of the Army), J.M. Lockhart, E.W. Pearson, B. Waddell, P.W. Wagner and the Grand Junction office of the Colorado Division of Wildlife for contributing data. An earlier draft of the manuscript was reviewed and im- proved by M.A. Bogan, W.R. Dryer, and R.L. Phillips. Literature Cited Arnell, W.B. 1971. Prey utilization by nesting Golden Eagles ( Acquila chrysaetos ) in central Utah. MS Thesis. Brigham Young University, Provo, Utah. Brown, L, 1977. Eagles of the world. Universe Books, New York. 244 pp. Camenzind, F.J. 1968. Nesting ecology and behavior of the Golden Eagle in west central Utah. Unpbl. Master’s Thesis. Brigham Young University, Provo, Utah. 40 pp. Edwards, T.C., Jr., and M.W. Collopy. 1983. Obligate and facultative brood reduction in eagles: an exami- nation of factors that influence fratricide. Auk 100:630-635. Fall 1984 Short Communications 113 Gordon, S. 1955. The Golden Eagle. Collins, London. 246 pp. Hickman, G.L. [no date.] Life history and ecology of the Golden Eagle in southwestern Idaho and southeastern Oregon. U.S. Fish and Wildlife Service Rep. 104 pp. Hinman, R.A. [no date.] Antelope populations in southwestern Utah with special reference to Golden Eagle predation. Completion Rep., Fed. Aid. Proj. W-65-R-6. 61 pp. Lish, J.W. 1975. Status and ecology of Bald Eagles and nesting of Golden Eagles in Oklahoma. MS Thesis. Oklahoma State University, Norman, OK. 98 pp. Lockhart, J.M. 1976. The food habits, status and ecol- ogy of nesting Golden Eagles in the Trans-Pecos re- gion of Texas. MS Thesis. Sul Ross State University, Alpine, Texas. 65 pp. , T.P. McEneaney, and R.L. Phil- lips. 1978. The effects of coal development on the ecology of birds of prey in southeastern Montana and northern Wyoming. Annual Progress Rep. 1978., Sec- tion of Wildlife Ecology on Public Lands, Denver Wildlife Research Center, Denver, Colorado pp. 9-14. , D.W. Heath, and C.L. Be- litsky. 1980. The status of nesting Peregrine Fal- cons and other selected raptor species on the Black Butte Mine Lease and adjacent lands. U.S. Fish and Wildlife Service - Final Rept. to the U.S. Bureau of Land Management and Peter Kiewit Sons’ Co. 59 pp. McGahan, J. 1966. Ecology of the Golden Eagle. MS Thesis, University of Montana, Missoula, MT. 78 pp. Murphy, J.R. 1975. Status of a Golden Eagle population in central Utah, 1967-1973. In: J.R. Murphy, C.M. White and B.E. Harrell (eds.) Population status of raptors. Raptor Res. Rep. No. 2. pp. 91-96 Murphy, J.R., F.J. Camenzind, D.G. Smith, and J.B. Weston. 1969. Nesting ecology of raptorial birds in central Utah. Brigham Young Univ. Sci. Bull., Biol. Ser. 10:1-36. Newton, I. 1979. Population ecology of raptors. Buteo Books, Vermillion, South Dakota. 399 pp. OlendOrff, R.R. 1976. The food habits of North American Golden Eagles. Amer. Midi, Nat. 95:231-236. Phillips, R.L., and A.E. Beske. 1981. Golden Eagles and coal development in the eastern Powder River Basin of Wyoming. Unpubl. Rep. U.S. Fish and Wildlife Service, Denver Wildlife Research Center, Denver, Colorado. 55 pp. Reynolds, H.V., III. 1969. Population status of the Golden Eagle in south-central Montana. MS Thesis. University of Montana, Missoula. MT. 61 pp. Steenhof, K., M.N. Kochert, and J.H. Doremus. 1983. Nesting of subadult Golden Eagles in southwstern Idaho. Auk 100:743-747. Trueblood, T. 1982. The great rabbit roundup. Field and Stream 86( 1 2) : 1 1 , 1 4, 1 6. White, C.M., and T.L. Thurow. 1984. Reproduction of Ferruginous Hawks exposed to controlled distur- bance. Condor (in press). U.S. Fish and Wildlife Service, Denver Wildlife Research Center, Building 16, Federal Center, Denver, CO 80225. Ad- dress of second author: U.S. Fish and Wildlife Service, Federal Building, Room 1311, 125 South State Street, Salt Lake City, UT 84138. Received 27 December, 1983; Accepted 11 June 1984. Food Piracy Between European Kestrel and Short-eared Owl Erkki KoRPiMaki I studied a raptor community of the large field plain of Alajoki in Southern Ostrobothnia, western Finland (63° 05 'N, 22°55'E), from 1977 through 1982 (see Korpimaki, etal. 1977, 1979). The most numerous raptor on the study area was the Short-eared Owl {Asio flammeus) (315 total pairs, 39.4%), followed by European Kestrel (Falco tin- nunculus) (36.2%), Long-eared Owl (A. otus) (20.0%), Northern Harrier ( Circus cyaneus) (2.5%), Boreal Owl (Aegolius funereus) (1.6%) and Sparrow Hawk (Accipiter nisus ) (0.3%); for addition details see Korpimaki 1984a). Although the 4 most common species comprise the guild of open-terrain hunting birds of prey in the study area (Korpimaki 1978, 1981), inter- and intra- specific food piracy or kleptoparasitism (see Brockmann and Barnard [21979] for additional details on the terms) was observed only once. Consequently this case may be of some interest. On 16 May 1982 at 2130 H, I saw a Short-eared Owl in the northern part of Alajoki flying over the field at the height of about 120 m and carrying a vole in its talons. The 114 Short Communications Vol. 18, No. 3 owl passed a male European Kestrel sitting on the roof of a barn. The kestrel chased the owl and struck it in the back. It attacked 3 times and the owl took shelter in high vegeta- tion near a ditch. The kestrel stopped attacking and re- turned to the roof of the same barn. The owl waited for a few minutes on the ground and then started to fly and hunt again. When I examined the location where the owl took shelter, I found a whole Common Vole ( Microtus arvalis), which was still warm, but no owl nest. The nest in this territory was found on 5 June, when the young were just hatching. Consequently the female was incubating in the middle of May, and the owl observed was probably the hunting male. The kestrel does not breed in the vicinity and was apparently not defending a nest. The proportion of Microtus voles (M. agrestis and M. arvalis) in the diets of raptors was studied in 1977, when it was 95.5% for Long-eared Owl, 97.6% for Short-eared Owl and 87.7% for European Kestrel (Korpimaki et al. 1977). As rodents are central also in the diet of Northern Harrier (in Norway 57%, Hagen 1952), voles are the most important prey item for raptors of Alajoki, although there are also some alernative prey groups available (e.g., shrews, mice, birds, lizards, frogs and insects; Korpimaki 1984b). Consequently, one might expect a keen inter- and intraspecific competition for food among these birds, especially when voles are scarce. Vole populations crashed in 1980-81 and were in the increase phase in 1982 (Kor- pimaki 1984a), wherefore a lack of food may have been the reason for piratical behaviour of the kestrel. Also, Brockmann and Barnard (1979) pointed out that klep- toparasitism occurs more frequently during years of a food shortage. The hunting Short-eared Owl flies near the ground and locates its prey by hearing and sight. The hunting technique of the owl is adapted to catching of prey animals in the high grass (for example in unculti- vated fields) better than that of the kestrel, which flies or hovers high in the air over the field (Korpimaki 1978). The Short-eared Owl is a vole specialist, while the kestrel preys opportunistically on shrews, birds, lizards, frogs and insects when voles are scarce (Korpimaki 1984b). Thus the Short-eared Owl can probably catch voles of lower densities compared with the kestrel, and it may be advan- tageous for the kestrel to rob food from Short-eared Owl, which is quite a slow flyer. Food piracy between the European Kestrel and Short- eared Owl is quite rare. I have found only 6 earlier cases described in literature (from Sweden, Mascher 1963, Nilsson 1975 and from Great Britain, Balfour 1973, Reese and Balfour 1973, Boyle 1974, Clegg and Henderson 1974). Dickson (1971) has described also an interaction of Short-eared Owl, European Kestrel and Northern Har- rier on same pipit prey. All above mentioned cases were observed from the end of winter to the beginning of summer when vole populations were at their lowest and the competition for food may have been keenest. Food shortage enhances kleptoparasitism among birds, espe- cially in falconiforms and charadriiforms (Brockmann and Barnard 1979). Food piracy is more general between open-country predators in central and western Europe than in my northern study area, because harriers can also take prey from Short-eared Owls (1 1 cases in Great Britain, Watson 1977 and in the United States, Berger 1958, Clark 1975). On the other hand, Short-eared Owl may sometimes adopt piratical behaviour. Wood (1976) has observed that the owl tried to take a small rodent from a Stoat (Mustela erminea); Bildstein and Ashby (1975) saw the owl robbing prey from Northern Harrier and Gordon Riddell (ac- cording to Mikkola 1983) described a Short-eared Owl attempting to take prey from a kestrel. This apparent difference in frequency of piratical behaviour between regions may be due to the cyclic fluctuations of the vole populations in northern Europe causing a higher degree of nomadism among raptors compared with a more stable food production in more southern areas where raptors tend to be resident. Most raptors migrate from my study area when voles are scarce (Korpimaki 1984a), and this behaviour decreases the competition for food. Acknowledgment I thank Mikko Hast for help in the field work, Clayton M. White and an anonymous reviewer for useful comments on my manus- cript as well as the Finnish Cultural Foundation, the Oulu Student Foundation, the Jenny and Antti Wihuri Foundation, the Emil Aaltonen Foundation and the Academy of Finland for financial support of my raptorial studies. Literature Cited Balfour, E. 1973. Food piracy between kestrel, short- eared owl and hooded crows. British Birds 66:227-228. Berger, D. 1958. Marsh hawk takes prey from short- eared owl. Wilson Bull. 70:90. Bildstein, K.L., and M. Ashby. 1975. Short-eared Owl robs Marsh Hawk of prey.AwA: 92:807-808. Boyle, G.L. 1974. Kestrel taking prey from short-eared owl. British Birds 67:474-475. Brockmann, H.J., and C.J. Barnard. 1979. Klep- toparasitism in birds. Animal Behaviour 27:487-514. Clark, R.J. 1975. A field study of the short-eared owl, Asio flammeus (Pontoppidan), in North America. Wild l. Monogr. 47:1-67. Clegg, T.M., and D.S. Henderson. 1974. Kestrel taking prey from short-eared owl. British Birds 64:317. Dickson, R.S. 1971. Interaction of Short-eared Owl, Kestrel and Hen Harrier over pipit prey. British Birds 64:543. Hagen, Y. 1952. Rovfuglene og viltpleien. Oslo. KoRPiMaki, E. 1978. Observations from hunting habits of seven raptorial species. Suomenselan Linnut 313:40-44, 86-89. Fall 1984 Short Communications 115 1981. On the ecology and biology of Tengmalm’s Owl (Aegolius funereus) in Southern Os- trobothnia and Suomenselka, western Finland. Acta Univ. Ouluensis ser. A. Sci. rerum not. 118 Biol. 13:1-84. . 1984a. Population dynamics of birds of prey in relation to fluctuations in small mammal populations in western Finland. Annales Zoologici Fen- nici 21 (in print), . 1984b. Optimal diet of the Kestrel Falco tinnunculus in breeding season. Ornis Fennica 61 (in print). . 1984c. Prey choice strategies of the Kestrel Falco tinnunculus in relation to small mammal abundance and Finnish birds of prey. Annales Zoologici Fennici 21 (in print). , S. Ikola, R. Haapoja, and J. KiRKKOMaki. 1977. On the ecology of Long-eared, Short-eared and Tengmalm’s Owls as well as Kestrel and Hen Harrier in Alajoki in 1977. Suomenselzn Lin- nut 12:100-117. . , E., S. Ikola, R. Haapoja, and O. Hem- minki. 1979. On the occurrence and breeding of raptors in Alajoki in 1978. Suomenselsin Linnut 14:44-51. Mascher, J.W. 1963. Tornfalk (Falco tinnunculus) over- tar byte fr&n jorduggla (Asio flammeus ) i flykten. Vdr Fdgelvdrld 22:293-294. Mikkola, H. 1983. Owls of Europe. T & A D Poyser, Calton. 397 pp. Nilsson, I. 1975. Tornfalk poarasiterar p& jorduggla. Anser 14:133. Reese, R.A., and E. Balfour. 1973. Food piracy bet- ween kestrels and short-eared owls. British Birds 66:227-228. Watson, D. 1977. The Hen Harrier, T&AD Poyser, Calton. 307 pp. Wood, C.R. 1976. Piratical short-eared owl. British Birds 69:272. Kp.4, SF-62200 Kauhava, FINLAND Received 17 December 1983; Accepted 4 June 1984 An Unusual Observation of ‘Homing’ To Prey By A Migrating Immature Peregrine Falcon Carl Safina On 6 October 1981 at 10:05 EST, while operating a raptor banding station on the Long Island, New York barrier beach, I saw a hatching year female Peregrine Falcon (Falco peregrinus) land approximately 50 m from my blind and begin eating a small passerine (probably a White-throated Sparrow (Zonotrichia albicollis , based on feathers). The falcon was on a low, beach heather ( Hud - sonia) covered rise in a broad, open rolling area. Soon after the falcon began eating, an Osprey (Pandion haliaetus), carrying a fish, came over the falcon, vocalizing. The Peregrine flew up and chased the Osprey over the bay to the north, stooping repeatedly at it before flying out of sight. Within 5 min the falcon reappeared on its kill. As the prey was small, cryptically colored, and in a broad, non-descript area of the beach, and since the Peregrine was not seen searching for it, apparently the falcon re- membered exactly where it had left its kill and was able to return there from a point out of sight. Falcons frequently return to cached prey. What is in- teresting about this incident is that the falcon was a first year migrant and the topography was almost certainly not familiar (the banding station had been manned daily for 3 w prior, and no Peregrines appeared to have been staying in the area). Enderson (Auk. 81:332-352, 1964) described wintering Prairie Falcons ( Falco mexicanus) leaving their prey on the ground and driving off other rapors in a similar manner. His falcons seldom had difficulty re- locating the prey, but this is not surprising because they were familiar with the area. National Audubon Society, Scully Sanctuary, 306 South Bay Avenue, Islip, NY 11751. Received 30 March 1983; Accepted 30 April 1984 Errata - Raptor Research 1 8(2) Page 44 (Table 1 concluded), 0.420 g should appear in the column for shell thickness, 0.49* 1 should appear in the column for HE and 0.2 7* 1 should appear in the column for DDE; page 47, paragraph 3, line 6, > 8 ppm should appear as >8 ppm; page 61, Literature Cited, the Sawbyetal. reference appeared in Condor 76:479-481; page 70, photographs are reversed. 116 News and Reviews Vol. 18, No. 3 “The Peregrine Falcon At Reelfoot Lake” By Murrell Butler Limited Edition Print of 2,500 A tree-nesting “Duck Hawk” populated the Mississippi and Ohio River areas in times past. A remnant nesting population was first documented during the 1930’s at Tennessee’s Reelfoot Lake by the late Albert F. Ganier. During the 1940’s a new nest site was discovered on the west side of the lake by Dr. Walter R. Spofford, then Professor of Anatomy at Vanderbilt University. Dr. Spofford and a few carefully selected observers made yearly nesting observa- tions until the early 1950’s. Mr. Thomas S. Butler was privileged to have been among those who spent many days recording the events of each year’s breeding season beneath the enormous cypress tree that served as the falcons’ nest site. During the late 1970’s a happy circumstance led Tom to meet Murrell Butler, a distant cousin from Louisiana. Murrell was an accomplished wildlife artist and became enthralled by the tales of a Peregrine Falcon that once nested in the snag of the mammoth cypress tree. A subsequent trip to the nest site (the cypress still stands!), the relocation of old photographs and consultation with friends and fellow falconers culminated in this magnificent painting by Murrell Butler. “The Peregrine Falcon at Reelfoot Lake” portrays the last known North American tree nest of the Peregrine. Available in a 16" by 20" limited edition print of 2500, the introductory price is $65.00 for prints #1 - #500. The introductory price includes postage within the fifty states and a $10.00 donation to The Raptor Research Foundation, Inc. The price will advance to $125.00 per print for #2001 - 2500, according to the following schedule: #1 - 500, $65.00; #501 - 1000, $75.00; #1001 - 1500, $85.00; #1501 - 2000, $95.00; #2001 - 2500, $125.00; Arkansas residents will need to add state, city and /or county sales tax). Prints may be ordered directly from Mr. Thomas S. Butler, Butler Galleries, 28 Fairmont Street, Eureka Springs, Arkansas 72632, USA. Payment may be made by check, money order, VISA or MASTERCARD. RAPTOR RESEARCH A Quarterly Publication of The Raptor Research Foundation, Inc. EDITOR: Clayton M. White, Department of Zoology, 161 Widtsoe Building, Brigham Young University, Provo, Utah 84602 ASSISTANT EDITOR: Jimmie R. Parrish, Department of Zoology, 159 Widtsoe Building, Brigham Young Univer- sity, Provo, Utah 84602 ASSOCIATE EDITORS Jeffrey L. Lincer - Environmental Chemistry and Toxicology Richard Clark - Order Strigiformes Ed Henckel - Family Cathartidae Gary E. Duke - Anatomy and Physiology Patrick T. Redig - Pathology, Rehabilitation and Reintroduction Jim Mosher - General Ecology and Habitat Analysis INTERNATIONAL CORRESPONDENT: Richard Clark, York College of Pennsylvania, Country Club Road, York, Pennsylvania 17405 Raptor Research (ISSN 0099-9059) welcomes original manuscripts dealing with all aspects of general ecology, natural history, management and conservation of diurnal and nocturnal predatory birds. Send all manuscripts for considera- tion and books for review to the Editor. Contributions are welcomed from throughout the world, but must be written in English. INSTRUCTIONS FOR CONTRIBUTORS: Submit a typewritten original and two copies of text, tables, figures and other pertinent material to the Editor. Two original copies of photographic illustrations are required. Raptor Research is published in a double-column format and authors should design tables and figures accordingly. All submissions must be typewritten double-spaced on one side of 8V£ x 11-inch (21 1/2 x 28cm) good quality, bond paper. Number pages through the Literature Cited section. The cover page should^contain the full title and a shortened version of the title (not to exceed 30 characters in length) to be used as a running head. Author addresses are listed at the end of the Literature Cited section. Authors should indicate if present addresses are different from addresses at the time the research was conducted. When more than one author is listed, please indicate who should be contacted for necessary corrections and proof review. Provide an abstract for each manuscript more than 4 double-spaced typewritten pages in length. Abstracts are submitted as a separate section from the main body of the manuscript and should not exceed 5% of the length of the manuscript. Acknowledgements, when appropriate, should immediately follow the text and precede the Literature Cited. Both scientific and common names of all organisms are always given where first appearing in the text and should conform to the current checklists, or equivalent references, such as the A.O.U. Checklist of North American Birds (6th ed., 1983). Authors should ensure that all text citations are listed and checked for accuracy. If five or fewer citations appear in the text, place the complete citation in the text, following these examples: (Brown and Amadon, Eagles, Hawks and Falcons of the World. McGraw-Hill, New York. 1968), or Nelson (Raptor Res. 16(4):99, 1982)). 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Tables are typewritten, double-spaced throughout, including title and column headings, should be separate from the text and be assigned consecutive Arabic numerals. Each table must contain a short, complete heading. Footnotes to tables should be concise and typed in lower-case letters. Illustrations (including coordinate labels) should be on 8 H x 1 1 -inch (2 1 Vz x 2 8cm) paper and must be submitted flat. Copies accompanying the original should be good quality reproductions. The name of the author(s) and figure number should be penciled on the back of each illustration. All illustrations are numbered consecutively using Arabic numerals. Include all illustration legends together, typewritten double-spaced, on a single page whenever possible. Line illustrations (i.e., maps, graphs, drawings) should be accomplished using undiluted india ink and designed for reduction by 1/3 to V 2 . Drawings should be accomplished usingheavy weight, smpoth finish, drafting paper whenever possible. Use mechanical lettering devices, pressure transfer letters, or calligraphy. Typewritten or computer (dot matrix) lettering is not acceptable for illustrations. Use of photographic illustrations is possible but requires that prior arrangements be made with the Editor and the Treasurer. A more detailed set of instructions for contributors appeared in Raptor Research, Vol. 1 8, No. 1 , Spring 1984, and is available from the Editor. NON-PROFIT ORG. U.S. POSTAGE PAID PERMIT #66 PROVO, UTAH