Simultaneous Multiple Clutches and Female Breeding Success in Mountain Quail

To evaluate the contribution of simultaneous clutches to breeding success in female Mountain Quail (Oreortyx pictus), we located nests of radio-marked male and female Mountain Quail in west-central Idaho from 1992 to 1995 and estimated rates and parameters of nesting success. In our sample, 29 females, 19 males, and 4 quail of unknown sex, including 12 apparently monogamous pairs, incubated nests. Using logistic regression, we found that constant survival and sex were the best-supported models to explain nest success for 45 nests of known age. Odds of success for male-incubated nests were 1.7-times (95% CI: 0.4–7.9) greater than for female-incubated nests. Mean clutch size for first nests was 11.8 (range: 6–16) and clutches incubated by males (12.6 ± 0.3 eggs) were significantly larger than female-incubated clutches (11.4 ± 0.4 eggs). Mean hatching date for all nests was 2 July (range: 10 June–23 July). Two of six females whose nests were depredated renested. Paired females produced an average of 24 eggs (range: 20–28). Mean hatching date for nine paired males was 30 June ± 3 days and 3 July ± 3 days for females. The estimated average number of days spent on nesting activities for nine successfully hatched pairs was 59 (range: 54–64). All 12 paired females hatched at least eight chicks from both clutches. Our findings indicate that simultaneous clutches in Mountain Quail ensures breeding success in females under conditions that may not be amenable to other forms of multiple brooding.

Male Incubation and Biparental Care in Mountain Quail

We examined the reproductive behavior of Mountain Quail (Oreortyx pictus) in two ecologically different regions of Oregon. We used radio-telemetry to locate 57 Mountain Quail nests and determine breeding behavior and incubation patterns. Mountain Quail appeared socially monogamous and displayed few alternative reproductive strategies; only one bird renested and no birds produced consecutive clutches. Twenty-five of 57 nests were incubated exclusively by males, 30 by females, and two by birds of undetermined sex. We observed no nest switching, and males and females had similar clutch and brood sizes. Males brooded chicks, frequently without female assistance. Within six radio-marked pairs, males and females simultaneously incubated separate nests <200 m apart. The average production by females was 22 eggs (range 19–26) with a mean clutch size of 11 eggs (range 7–15). Simultaneous multiple clutches may enhance the reproductive potential of a species when environmental conditions limit double brooding or renesting, and may increase the likelihood that some broods will survive high levels of nest and brood predation. Incubación por Machos y Cuidado Biparental en Oreortyx pictus Resumen. Examinamos el comportamiento reproductivo de Oreortyx pictus en dos regiones ecológicamente diferentes de Oregon. Utilizamos radiotelemetría para localizar 57 nidos de O. pictus y para determinar el comportamiento reproductivo y los patrones de incubación. O. pictus resultó ser socialmente monógamo y mostró unas pocas estrategias de reproducción alternativas; sólo un ave volvió a nidificar y ningún ave produjo nidadas consecutivas. Veinticinco de 57 nidos fueron incubados exclusivamente por machos, 30 por hembras y dos por aves de sexo indeterminado. No observamos intercambio entre nidos y tanto hembras como machos tuvieron nidadas y crías de tamaños similares. Frecuentemente los machos criaron a los polluelos sin la asistencia de las hembras. Considerando seis parejas marcadas con transmisores, hembras y machos incubaron simultáneamente nidos separados por <200 m. La producción promedio por hembra fue de 22 huevos (rango entre 19–26), con un tamaño promedio de nidada de 11 huevos (rango entre 7–15). Las nidadas múltiples simultáneas pueden aumentar el potencial reproductivo de una especie cuando las condiciones ambientales limitan la doble cría o la re-nidificación y aumentar la probabilidad de que algunas crias sobrevivan, dados los altos niveles de depredación de nidos y crías.