SEASONAL STATUS OF THE AMERICAN PIPIT IN IDAHO DANIEL M. TAYLOR, 244 N. 12th, Pocatello,Idaho 83201 In Idaho, the AmericanPipit (Antbus rubescens)has been considered primarilya migrant,either locally common but erratic (Larrison et al. 1967) or uncommonin springand commonin fall (Burleigh1972). Severalother writers(Merriam 1891, Merrill 1898, Newhouse1960, Levy 1962) consid- ered it an abundantfall migrantbut gaveno indicationof actualnumbers. The one (Larrisonet al. 1967) or two (Burleigh1972) winterrecords were from Lewiston.Larrison et al. (1967) suspectedthat pipitsmight breed on someof the state'shigh mountains,while Burleigh(1972) knew of only Merriam's(1891) statementthat they breedin the Salmon River Mountains and a report by L. B. McQueenof breedingin the upper Pahsimeroi drainagenear Borah Peak. This scantinessof breedingevidence may be why the mostrecent A.O.U. checklist(1983) statesthat the AmericanPipit breedslocally on mountaintopsin severalRocky Mountain states but does not specificallylist Idaho. In this paper I consolidateand enhancewhat is known aboutAmerican Pipit distributionin Idaho with reference to adjacent areas. I present evidenceof additionalbreeding, concentrations of thousandsof fall mi- grants,and the species'regular but erraticwintering in much of southern Idaho.I analyzeChristmas Bird Countdata for patternsin winterdistribu- tion relatedto differencesin weather,elevation, geography, and annual variability. METHODS I gatheredrecent American Pipit recordsfrom a literaturereview and my own fieldnotes for the last 15 years.All ChristmasBird Counts(CBCs) for Idahosince 1978 were included,as well as somefrom adjacentMontana and Washington.Long-term counts from southernIdaho were examined statisticallyin a mannersimilar to that of Lauranceand Yensen(1985) and Dunning and Brown (1982). Weather data were extracted from U.S. EnvironmentalData Servicemonthly reports from eachweather station in or closeto eachCBC. Usingnumber of birdsper party-hour,I compared differencesbetween areas and betweenyears by analysisof variance (ANOVA),and examinedinfluences of weatherand elevationby multiple regression(Zar 1974). This wasdone on a MacintoshSE computerwith a Statviewstatistical package. I alsosurveyed the extensivemudflats at the mouthof the New York Canal, Lake Lowell,Canyon Co., for American Pipits18 timesfrom August through November 1990. RESULTS Breeding In the SawtoothMountains I observedan adultAmerican Pipit feeding a youngbird on the CusterCo. sideof the summitalong the trail between Western Birds 25:43-49, 1994 43 AMERICAN PIPIT IN IDAHO Toxawayand Alice lakes,elevation 2775 m, on 26 July1989 andan adult behavingterritorially near Alpine Lake, CusterCo., elevation2625 m, on 3 August 1993 (Figure 1). I found a pair of pipits giving alarm calls and carryingfood in theirbeaks in the Henry'sLake Mountains,elevation 2850 m, FremontCo., on 29 July 1993. C. Trost (pers.comm.) found several nestingpairs with young at the headof the eastfork of the PahsimeroiRiver on 25 July1976 [AmericanBirds (AB) 30:981] and a neston Leatherman Peak,Big LostRange, Custer Co., elevationabout 3200 m. Roberts(1992) foundAmerican Pipits in the nestingseason between 2400 and 3050 m in the Lemhi and Beaverhead ranges and at Long Tom Lookout, ChallisCreek Lakes, and Taylor Mountainbetween the Middle Fork and main Salmon Rivers. These locationsmight be consideredpart of the Salmon Mountainsof Merriam (1891). FallMigration At Lake Lowell (Figure1) in 1990, no AmericanPipits occurredin August,and I foundonly one to fouron fivedates from 6 to 18 September. On 27 Septemberthere were 600, and numberspeaked at 1750 on 9 October.There were stillhundreds by 16 and 18 October,and from late Octoberto mid-Novemberdozens remained. A few lingeredinto December. At thissame location J. Gatchetestimated pipits gathered in the thousands in the lastweek of September1991 (AB 46:125). Largenumber of pipitshave been reported from otherlocations in Idaho and adjacentareas in lateSeptember or October.Thousands were at Rupert in fall 1971 (AB 26:98). I foundflocks of over100 on farmlandin the Dry Lake regionof CanyonCo. in the lastweek of October1976, and 140 at AmericanFalls Reservoir, Power Co., on 22 September1990. In eastern Washington500 wereat BanksLank on 17 September1983 (AB 38:226), 200 were at Spokane on 8 October 1972 (AB 27•0), 2000 were at O'SullivanDam on 9 Oct 1971 (AB 26:91), and at least 1000 were near Reardan on 21 September 1973 (AB 28:81). Hundreds were found in alpinemeadows on SteensMountain, Oregon, on 24 September1983 (AB 38:226), 2000 were estimatedat BrighamCity, Utah, on 22 October 1972 (AB 27:298), and thousandswere in Cache Valley, Utah, on 5 October 1942 (Bent 1950). Winter In winter,the AmericanPipit is unrecordedfrom northern Idaho, except at Lewiston,the state'slowest elevation, where Burleigh (1972) livedfrom 1948 to 1958 andrecorded pipits only twice: a singlebird on 21 December 1951 and a flock of 60 on 8 and 13 January1954. The 33 CBCs conductedat Moscow,Indian Mountain,Sandpoint, and Coeur d'Alene from 1978 to 1991 recordedno pipits.There were also no pipitson the northwesternMontana and easternWashington CBCs at Troy, Libby, GlacierNational Park, Big Fork, or Spokaneduring this time. In central Idaho,the two CBC areasof Sun Valleyand Salmonrecorded pipits just once in 14 years,but a total of 86 at Salmon in December1986. The Missoula,Montana, CBC has had justone pipit once, and a recordfor 17 44 AMERICAN PIPIT IN IDAHO December1989 at NinepipeNWR (AB 44:297) was apparentlyonly the second for western Montana in winter. Pipitshave been found erraticallyin winter on CBCs in southernIdaho (Table1). Perhapsbecause of high variability,there were no significant differencesin numbersof pipitsbetween any of the nine southernIdaho CBC areas(ANOVA, P > 0.10 in all comparisons;Bruneau was excluded owingto its shortduration). Pipits have been recorded in about45% of the yearson the sevenof the ten CBCswhere they havebeen found more than once, but no count found them more than 58% of the time. The highest BRITISH COLUMBIA n Glacier N,P. 0 Troy nt[] Libby g o BigFork Spokane 0 Coeur 'd MONTANA Moscow O Mtssoula Lewtston' o o Salmor o Henrys Mountatns ß o SawtoothMountains ß Big Lost ß 0 0 Rexl' Nampa Sun Valley Boise Falls 0 Bruneau Hagerman ] lcan Fails Reservoir Falls Rupert NEVADA UTAH Figure1. Locationsmentioned in the text. Solidcircles, known breeding locations; open circles,probable breeding locations; solid squares, locations of ChristmasBird Counts. 45 AMERICAN PIPIT IN IDAHO Table 1 Numbersof AmericanPipits on ChristmasBird Counts in Southern Idaho from 1978 to 1991 Elevation Yearsof High Mean_+ SE a (Range) Area (feet) count count pipits/party-hour Nampa 2210 14 (7)b 242 0.327_+ 0.223 (0-3.15) Bruneau 2455 7 (4) 326 1.601 _+1.306 (0-9.30) Boise 2700 14 (5) 30 0.039 _+0.022 (0-0.95) Hagerman 2900 13 (6) 34 0.135 _+0.072 (0-0.95) Twin Falls 3170 12 (4) 423 1.174 _+1.096 (0-13.22) Rupert 4150 14 (6) 70 0.382 _+0.277 (0-3.91) Am. Falls 4180 14 (8) 23 0.059 _+0.023 (0-0.29) Pocatello 4200 14 (1) 1 0.001 _+0.001 (0-0.02) IdahoFalls 4610 14 (0) 0 0 Rexburg 4800 14 (1) 200 0.510 _+0.510 (0-7.14) aSE,standarderror. /•Numberof yearswith pipits on count. numberon any count was 423 at Twin Falls in 1986, and Nampa, Bruneau,and Rexburgeach had a singlecount with over 100 pipits. Althoughthe three southernIdaho CBCs at the highestelevations recordedpipits on onlytwo of 42 counts,pipit numbers were not signifi- cantlycorrelated with elevation(Table 2). Therewas no significantassocia- tionof the abundanceof AmericanPipits on CBCswith the climatic factors of minimum snow, mean Decembertemperature, or mean December precipitation(Table 2). The 200 pipitsin 1979 constitutingRexburg's only recordwas one of the fewyears there without snow on the ground,and the Twin Fallspeak of 423 alsocoincided with a CBC free of snow.However, therewere 3 inchesof snowin Nampawhen 175 pipitswere found, while Bruneau recorded 279 with one-half inch of snow and 44 with 3 inches of snowand temperaturesof -22 to -32 ø C. Table 2 Relation of Various Climatic Factors and Elevation with American Pipit Numbers on Combined Idaho Christmas Bird Counts, 1978-1991 a Factor F testa Minimumsnow depth 0.547 (0.593) 0.46 (0.44) 0.01 (0.01) Elevation 1.303 (0.414) 0.28 (0.52) 0.02 (0.01) Mean Decemberprecipitation 0.008 0.928 <0.01 MeanDecember temperature 1.731 0.19 0.02 aF-testvalues of multipleregression for all counts,and in parenthesesall countsexcept IdahoFalls, Rexburg, and Pocatello,excluded because of theirhigher elevation. /•Probabilityvalues of F tests. CAmountof variationexplained by thesefactors. 46 AMERICAN PIPIT IN IDAHO For all southernIdaho CBCs combined(Bruneau excluded because of its shorter duration), numbersoi: pipits were highest in 1979, 1981, and 1986. The numberof pipitsper party-hourwas significantly higher in 1986 than in mostother years (ANOVA, P < 0.05), but thiswas probably due to the singlevery largetotal at Twin Falls.In yearswith few birds,pipits were stillfound on at leasttwo CBCs, exceptin 1983 when only four birdswere at Rupert.In the three yearswith the highestcounts three or four CBC areasstill lacked pipits. DISCUSSION The two new definitebreeding records and other midsummerobserva- tions further establishthe American Pipit as a breedingspecies in Idaho. The alpinezone in the statehas been inadequatelysurveyed, and it is likely there are more areasin the high countrythat supportpipits, especiallyas breedingpipits are known from adjacent