NECK COLLAR RETENTION IN DUSKY CANADA GEESE
--A total of 4965 Dusky Canada Geese (Branta canadensis occidentalis) were neckcollared on the Copper River Delta, Alaska, in 1984-1990. Collar retention rates for adult geese were obtained from examination of 910 recaptures. The effects of sex, collar age and collaring year on retention rates were determined using logit models. As there was a significant interaction between the effects of sex and collar age on retention rates, the sexes were modeled separately. The average annual retention rate for female geese (0.875 ___ 0.163 SE) was independent of all effects considered. Retention rates for males was influenced by collar age and the year collared. It is concluded that collar losses were substantial and that losses pecific to the years modeled should be considered in any population model. RETENCI•N DE ANILLOS EN EL PESCUEZO POR PARTE DE INDIVIDUOS DE BRANTA 1⁄2ANADENSIS OCCIDENTALIS Sinopsis.--Entre el 1984-1990 un total de 4965 individuos de gansos del Canada (Branta canadensis occidentalis) fucron anillados cn la pescuezo en el delta del Rio Copper, Alaska. La retenci6n de las anillas, pot parte dc adultos, fue obtenida del estudio de 910 individuos rccapturados. E1 efecto dcl sexo, edad dc la anilla y afio de la anillada, en la tasa de retcnci6n de anillas, fuc determinada utilizando modelos dc "logit." Como hubo una interaccion significativa entre el efecto del sexo y edad de la anilla, en la tasa de retenci6n, se hicieron modelos separados para ambos sexos. La retenci6n promcdio anual para hembras (0.875 + 0.163 EE) result6 set indepcndiente dc todos los otros efectos considerados. La tasa dc rctcnci6n cn los machos fue influcnciada pot la cdad de la anilla y el afio dc anillamiento. Sc concluye quc las p6rdidas de las anillas fue sustancial, y quc los extravlos en aftos particulates deben set consideradas en cualquier modelo poblacional. Neck collars have been used to mark geese for several decades (Marion and Shamis 1977). Observations of these birds have provided much valuable information about population dynamics (Hestbeck and Malecki 1989, Rusch et al. 1985), migration (Craven and Rusch 1983, Koerner et al. 1974, Raveling 1978, Trost et al. 1980), and behavior (Macinnes and Lieff 1968). Recently, observations of marked geese have been applied in methods used to estimate survival probabilities (Ebbinge and van Biezen 1987, Hestbeck and Malecki 1989, Raveling and Zezulak 1988, Rusch et al. 1985, Yparraguirre 1982), statistics that have traditionally been calculated from models utilizing band recovery data (Brownie et al. 1985). These models generally do not account for marker loss (Brownie et al. 1985, Pollock and Raveling 1982), which is probably of little consequence for-short lived species. In the case of potentially long-lived animals such as geese, however, marker loss may severely affect survival estimates (Nelson et al. 1980). The Dusky Canada Goose (Branta canadensis occidentalis), which nests primarily on the Copper River Delta, Alaska, and winters in the Willamitte Valley in Oregon and southwestern Washington, has steadily declined in number since 1979. Harvest was restricted in 1984 and is
AN ANNOTATED BIBLIOGRAPHY OF BIRD MARKING TECHNIQUES
A massive proliferation of bird marking techniques has occurred in recent decades as ornithologists have improved old methods or developed new methods to facilitate field investigations. Before beginning a bird marking study, an ornithologist has traditionally been faced with a review of voluminous literature available in various scattered journals and reports. Two decades ago, Cottam (1956) published an excellent review of bird marking techniques. More recently, Cogswell (1973) provided a worthwhile tabular summary of several color-marking methods currently being used, but his paper did not suggest advantages and disadvantages or list references for each technique. The present paper is an attempt to summarize, through 1975, the various techniques used on North American birds and the advantages or disadvantages of each technique. As with any similar undertaking, we have tried to examine the literature thoroughly and have probably overlooked a few important works. We apologize to those authors we have inadvertently neglected and would appreciate being informed of misinterpretations and omissions. Scientific names were taken from the American Ornithologists' Union Check-list (1957) and two recent supplements (Auk, 9•:411-419, 1973 and 93:875-879, 1976). Field recognition of birds has frequently been facilitated by attachment of various devices, alteration of the bird's appearance, or a combination of these. For a marker to be useful, it should meet most of the following criteria: Involve no immediate or potential hindrance or irritation marked bird.
BREEDING BEHAVIOR OF IMMATURE MOURNING DOVES
Some immature mourning doves (Zenaidura macroura) are capable of breeding in their first (calendar) year of life. The breeding activities of immatures observed in this study included calling, copulating, and nesting. Development of sexual structures such as cloacal papillae, oviduct openings, and gonads was also regarded as evidence of breeding potential. Immatures were identified princi- pally by white-tipped wing coverts. Sexes were distinguished by behavioral characteristics. Males coo, perform flights, carry nest material, and attend nests during the day and females attend nests at night. Immatures were involved in at least ten nestings on two areas near Tucson, Arizona, in 1963. Five young fledged from these nests.