The effects of diet-shifting from invertebrates towards fruit on the condition of autumn-migrant Catharus thrushes.

Migration is an energetically challenging and risky life history stage for many animals, but could be supported by dietary choices en route, which may create opportunities to improve body and physiological condition. However, proposed benefits of diet shifts, such as between seasonally available invertebrates and fruits, have received limited investigation in free-living animals. We quantified diet composition and magnitude of autumn diet shifts over two time periods in two closely-related species of migratory songbirds on stopover in the northeastern U.S. (Swainson's thrush [Catharus ustulatus], long-distance migrant, N = 83; hermit thrush [C. guttatus], short-distance migrant, N = 79) and used piecewise structural equation models to evaluate the relationships among (1) migration timing, (2) dietary behavior, and (3) morphometric and physiological condition indices. Tissue isotope composition indicated that both species shifted towards greater fruit consumption. Larger shifts in recent weeks corresponded to higher body condition in Swainson's, but not hermit thrushes, and condition was more heavily influenced by capture date in Swainson's thrushes. Presence of "high-antioxidant" fruits in fecal samples was unrelated to condition in Swainson's thrushes and negatively related to multiple condition indices in hermit thrushes, possibly indicating the value of fruits during migration is related more to their energy and/or macronutrient content than antioxidant content. Our results suggest that increased frugivory during autumn migration can support condition, but those benefits might depend on migration strategy: a longer-distance, more capital-dependent migration strategy could require stricter regulation of body condition aided by increased fruit consumption.

Physiological indicators of habitat quality for a migratory songbird breeding in a forest invaded by non-native Japanese barberry (Berberis thunbergii).

Non-native, invasive plants can impact birds by altering food sources, nesting substrates and other critical resources. Japanese barberry (Berberis thunbergii) is one of the most invasive, non-native woody plants in in the northeastern USA, and yet almost nothing is known about its effects on birds or other wildlife. To investigate individual-level impacts of Japanese barberry on a forest-breeding bird, we compared food abundance (leaf-litter arthropod biomass) and the physiological condition of territorial male ovenbirds (Seiurus aurocapilla) between areas of a forest preserve in New York State that had high or low densities of Japanese barberry. We used haemoglobin and plasma triglyceride concentrations to indicate energetic condition, plasma uric acid and total plasma protein levels to indicate diet quality, and heterophil to lymphocyte ratios to indicate chronic stress. We found no difference in arthropod biomass between ovenbird territories that were heavily invaded by or relatively free of Japanese barberry. Perhaps largely as a result, we found no relationship between Japanese barberry density and any of our five haematological condition indices. There was also no difference in body mass, body size or age ratio between ovenbirds nesting in areas with low or high densities of Japanese barberry to suggest that relatively uninvaded forest patches were in greater demand and acquired by the most dominant individuals. Our results indicate that Japanese barberry does not reduce habitat quality for breeding male ovenbirds in a way that affects their prey abundance or physiological condition, but we caution that other species of birds and other aspects of habitat quality could be affected differently. We encourage future research on additional bird species and the effects of Japanese barberry on factors such as diet composition, pairing and nesting success and post-fledging survival to improve science-based decision-making about the extent to which conservation resources should be applied towards Japanese barberry control.

Scheduled and unscheduled bleeding patterns with two combined hormonal contraceptives: application of new recommendations for standardization.

OBJECTIVE: To reassess and compare cycle control attained with two combined hormonal contraceptives, norgestimate (NGM)/ethinyl estradiol (EE) 25 microg and norethindrone acetate (NETA)/EE 20 microg, by new general criteria recommendations for all combined hormonal contraceptives. DESIGN: Analysis of bleeding data for cycles 1-6 from a randomized, multicenter trial. SETTING: 221 North American centers. PATIENT(S): Healthy, sexually active women (18-45 years old). INTERVENTION(S): NETA/EE: 1 mg NETA/20 microg EE, days 1-21 of each cycle and 75 mg of ferrous fumarate, days 22-28; NGM/EE: triphasic NGM in 7-day increments (days 1-7: 180 microg; days 8-14: 215 microg; days 15-21: 250 microg) and 25 microg EE, placebo on days 22-28. MAIN OUTCOME MEASURE(S): Cycle control evaluated from patients' daily diaries. RESULT(S): For cycles 1-6, there was a statistically significant lower incidence of unscheduled bleeding/spotting with NGM/EE 25 microg (range 21.0%-34.4%) than with NETA/EE 20 microg (range 33.0%-46.6%). Of the women who had unscheduled bleeding/spotting, the mean number of days per cycle of bleeding/spotting was comparable. A statistically significant higher incidence of scheduled bleeding was seen with NGM/EE 25 microg (95.2%-97.5%) than with NETA/EE 20 microg (78.5%-84.2%). CONCLUSION(S): The NGM/EE 25 microg has a lower incidence and comparable length of unscheduled bleeding and a higher incidence of scheduled bleeding than NETA/EE 20 microg in this post hoc analysis.