Site Fidelity, Philopatry, and Survival of Promiscuous Saltmarsh Sharp-Tailed Sparrows in Rhode Island

We investigated site fidelity and apparent survival in a promiscuous population of Saltmarsh Sharp-tailed Sparrows (Ammodramus caudacutus) in southern Rhode Island. Based on capture–recapture histories of 446 color-banded sparrows studied from 1993 to 1998 at our primary study site, Galilee, we observed significant variation in apparent survival rates among years, but not between sexes. Return rates of adult males (37.6%) and females (35.6%) were not significantly different during any year. Juveniles exhibited high return rates, ranging from 0 to 44%, with males (61% of returns) more likely to return than females (35%). In addition, we monitored movements of 404 color-banded sparrows at nine satellite marshes in 1997 and 1998, which supported our findings at Galilee and documented intermarsh movements by 10% of all banded birds. Lack of gender-bias in adult dispersal and strong natal philopatry of sparrows in Rhode Island occurs regularly among passerines possessing a variety of mating systems. Despite emancipation from parental and resource defense duties, adult male Saltmarsh Sharp-tailed Sparrows exhibited apparent survival rates similar to adult females. Availability of high-quality breeding habitat, which is patchy and saturated, may be the most important factor limiting dispersal for Saltmarsh Sharp-tailed Sparrows in Rhode Island

Effectiveness of AV-1011® to Reduce Damage to Drill-Planted Rice From Blackbirds

We determined efficacy of AV-1011® (a 50% anthraquinone product; Arkion® Life Sciences, New Castle, Delaware) on drill-planted rice seed to reduce blackbird damage and determine residue levels of anthraquinone (AQ) in rice seeds and seedlings and in the mature rice crop under field enclosures at the University of Missouri-Delta Center farm near Portageville, Missouri. Red-winged blackbird (Agelaius phoeniceus) damage was higher for untreated than AV-1011® treated rice seedlings at assessment period 3, 15 days postplanting (F1,141 = 15.81, P \u3c 0.001), and at assessment period 4, 19 days postplanting (F1,136 = 11.54, P = 0.001). Blackbird damage to AV-1011-treated seedling for assessment periods 3 and 4 was 8% and 7%, respectively, while blackbird damage to untreated seedlings during the same assessment periods was 52% and 44%. More blackbirds used untreated plots than AV-1011-treated plots during assessment periods 2–4 (F1,17.8 = 20.02, P \u3c 0.001). Overall concentrations of AQ on seeds averaged 5,993 μg/g or 0.59% during the test period. Concentrations of AQ in mature rice seed and plant collected at harvest averaged 1.22 μg/g and 0.10 μg/g, respectively. AV-1011 offers promise for reducing bird depredations to newly planted rice, but additional testing should be conducted to evaluate this repellent in a large-scale field setting

Nesting ecology of saltmarsh sharp-tailed sparrows in a tidally restricted salt marsh

We investigated population size, nest success, and nest-site characteristics of Saltmarsh Sharptailed Sparrows (Ammodramus caudacutus) from 1993 to 1998 in a salt marsh near Galilee, Rhode Island. From 1956 to 1997, tidal flow was restricted in the marsh by construction of a road with small culverts, which resulted in conversion of the marsh from short- and tall-form cordgrass (Spartina alterniflora) and marsh hay (S. patens) to one dominated by \u3e5 m tall common reed (Phragmites australis). In fall 1997, self-regulating tide gates were installed to restore the historic tidal regime and vegetation. We documented declines in adult sparrow population sizes (17-25% annual decline) and productivity (48% annual decline) while the tidal regime was restricted. Nest success was variable (10-83%) before 1998, with predators accounting, and short common reed. After restoration, sparrows nested where vegetation was taller, which permitted greater nest elevation. However, 91% of nests failed due to flooding following installation of new tide gates. We hypothesize that restoration efforts will have short-term negative impacts on Saltmarsh Sharptailed Sparrow populations until salt marsh habitats are restored in higher sections of the marsh

Natural Regeneration Processes in Big Sagebrush (Artemisia tridentata)

Big sagebrush, Artemisia tridentata Nuttall (Asteraceae), is the dominant plant species of large portions of semiarid western North America. However, much of historical big sagebrush vegetation has been removed or modified. Thus, regeneration is recognized as an important component for land management. Limited knowledge about key regeneration processes, however, represents an obstacle to identifying successful management practices and to gaining greater insight into the consequences of increasing disturbance frequency and global change. Therefore, our objective is to synthesize knowledge about natural big sagebrush regeneration. We identified and characterized the controls of big sagebrush seed production, germination, and establishment. The largest knowledge gaps and associated research needs include quiescence and dormancy of embryos and seedlings; variation in seed production and germination percentages; wet-thermal time model of germination; responses to frost events (including freezing/thawing of soils), CO2 concentration, and nutrients in combination with water availability; suitability of microsite vs. site conditions; competitive ability as well as seedling growth responses; and differences among subspecies and ecoregions. Potential impacts of climate change on big sagebrush regeneration could include that temperature increases may not have a large direct influence on regeneration due to the broad temperature optimum for regeneration, whereas indirect effects could include selection for populations with less stringent seed dormancy. Drier conditions will have direct negative effects on germination and seedling survival and could also lead to lighter seeds, which lowers germination success further. The short seed dispersal distance of big sagebrush may limit its tracking of suitable climate; whereas, the low competitive ability of big sagebrush seedlings may limit successful competition with species that track climate. An improved understanding of the ecology of big sagebrush regeneration should benefit resource management activities and increase the ability of land managers to anticipate global change impacts. © 2014 The Society for Range Management.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information