NOTES

CASSlN'S SPARROW NESTING IN

ROBERT D. DORN and JANE l_. DORN, Box 1471, Cheyenne,Wyominõ 82003

Cassin'sSparrow (Aimophila cassinii) was first reported in Wyomingon 8 June 1978 near Columbine,northeastern Natrona County, in the centralpart of the state (Faaneset al. 1979). Another was reportedin 1989 east of Glendo Reservoirin PlatteCounty (Bill Hayes pers. comm.). On 28 June 1990, WilliamHowe of the U. S. Fishand WildlifeService found four singingmales east of Torringtonin Goshen Countynear the Nebraskaborder (Ritter 1990, Kingery1990, Scott1993). Singing maleswere reportedannually from the samearea from 1991 (RitterI99I, Kingery 1991) through1994 (O. K. Scottin litt.).We hadbeen studying the vegetation of this area since 1986 but alwaystoo early or too late in the seasonto see or hear these sparrows.In I993, we scheduledour work in this area periodicallythroughout the summerand plannedto watch for the sparrows. On our first visit of 1993, on 13 June, we did not see or hear any Cassin's Sparrows,but on our secondvisit, on 22 June,we observedseveral singing males. We continuedto seesinging males on subsequentvisits: 27 Juneand 17, 24, and 31 July. On 31 July, while drivingdown a little-usedtrail 6.5 km east-northeastof Torrington(T24N, R60W, northhalf of the northhalf of section6), wherewe earlier had observeda singingmale, we flushedan adult with insectsin its beak. We immediatelystopped the vehicle,hoping to observean adultfeeding young. In a few minutes,the adultreappeared and landedabout 25 m in front of us. A few minutes later,we saw the adultsneaking through the brushabout 10 m from the vehicle.It then went behindus and finallywe heard youngbeing fed, but we were unableto pinpointthe location.The samepattern of feedingcontinued for about2 hours,but we still couldnot locate the young or determineif they were in the nest or not. Finally,we decidedto rushin the directionof the feedingon the nextvisit of an adult. When we did, the adult flushedfrom within I m of the rear of the vehicle.On examiningthe brushhere, we immediatelyfound the nest, which containedthree leatheredyoung and one unhatchedegg. On beingdiscovered, the young(Figure 1) promptlyabandoned the nestand ran intothe surroundingbrush. The nestmeasured 90 x 100 mm outsidediameter,. 70 x 64 mm insidediameter, and 50 mm deep (Figure2). It waslined with fine grass.The eggwas white with no markings(Figure 2) and measured19 x 16 min. The nestwas about 15 cm abovethe groundin a Sand Sagebrush(Artemisia filifolia). This appearsto be the first recordof the Cassin's Sparrow nestingin Wyoming. The habitathere is largelyconsolidated rolling sandhills with the relief averaging about15 meters.We estimatedtotal vegetation cover at 60%. The mostconspicuous is SandSagebrush. It averagesabout 5 dm high, and we estimatedits coverat about 30%. Other common speciesinclude the Prairie Sandreed(Calamovilfa longifolia), Sand Bluestem(Andropogon hallii), Prickly Muhly (Muhlenbergia pungens),Blowout Grass (Redfieldia fiexuosa), Spanish Bayonet (Yucca glauca), and Red-fruitPrickly Pear (Opuntia macrorhiza).Andrews and Righter(1992) and Rosche(1994) reportedthis same habitat for the speciesin Coloradoand , respectively. On 15 August,we againvisited the area and observedone adultwith one juvenile and anothersingle juvenile. On 28 August,we observedseveral adults and several independentjuveniles in smallloose feeding flocks with Brewer's(Spizella breweri), Chipping (S. passerina), Clay-colored (S. pallida), and Vesper (Pooecetes gramineus)sparrows and Lark Buntings(Calamospiza melanocorys). On 12 Sep- tember,we sawno Cassin'sSparrows, but the otherspecies that we observedon our previousvisit were stillthere. Duringthe nestingseason, the only sparrowsthat we 104 Western Birds 26:104-106, 1995 NOTES

Figure 1. YoungCassin's Sparrow that abandonedthe nest on discovery,31 July 1993, GoshenCounty, Wyoming.

Figure2. Cassin'sSparrow nest in SandSagebrush with one unhatchedegg, 31 July 1993, GoshenCounty, Wyoming. Three leatheredyoung abandoned the neston discovery.

105 NOTES

saw in the area were the Grasshopper (Ammodramus savannarum), Lark (Chondestesgrammacus), and Vesperand Lark Bunting.The $pizellae observedin Augustand Septemberrepresent transients. In 1994, we searchedfor Cassin'sSparrows in otherareas of SandSagebrush in Goshenand Platte counties,Wyoming, but we foundnone. No other areashad this communityas well developedas where the sparrowswere nesting. Faaneset al. (1979) reporteda northwardrange extensionof Cassin'sSparrows into Nebraskaand beginningabout 1974. The colonyin Goshen County,Wyoming, may date from approximatelythat time.

LITERATURE CITED

Andrews,R., and Righter,R. 1992. ColoradoBirds. Denver Mus. Nat. Hist., Denver. Faanes,C. A., Hanson, B. A., and Kantrud,H. A. 1979. Cassin'sSparrow--First recordfor Wyomingand recentrange extensions. W. Birds10:163-164. Kingery, H. E. 1990. The nestingseason. Mountain West region. Am. Birds 44:1161-1164. Kingery, H. E. 1991. The nestingseason. Mountain West region. Am. Birds 45:1141-1144. Ritter,S. 1990. Fieldnotes. Drumming Post (Wyo. Game and FishDept.) 3(4):8. Ritter,S. 1991. Fieldnotes. Drumming Post (Wyo. Game and FishDept.) 4(3):3. Rosche,R. C. 1994. Birdingin westernNebraska. Part II. Birding26:416-423. Scott, O.K. 1993. A Birder'sGuide to Wyoming.Am. BirdingAssoc., Springs.

Accepted 10 February 1995

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