Catalogue of candidate emission-line objects in the Small Magellanic Cloud

H\alpha and [O III] narrow band, wide field (7 * 7 degree), CCD images of the Small Magellanic Cloud were compared and a catalogue of candidate planetary nebulae and H\alpha emission-line stars was compiled. The catalogue contains 131 planetary nebulae candidates, 23 of which are already known to be or are probable planetary nebulae or very low excitation objects. Also, 218 emission-line candidates have been identified with 113 already known. Our catalogue therefore provides a useful supplement to those of Meyssonnier & Azzopardi (1993) and Sanduleak, MacConnell & Davis Phillip (1978). Further observations are required to confirm the identity of the unknown objects.Comment: 8 pages, accepted by MNRA

Body Size and Condition, Timing of Breeding, and Aspects of Egg Production in Eastern Kingbirds

Variation in timing of breeding in Eastern Kingbirds (Tyrannus tyrannus) was correlated only weakly with external morphological characters, but was correlated positively and significantly with estimates of body size based on measurements of skeletons and muscle weights. Small females apparently held a reproductive advantage in being able to mobilize resources for reproduction before large females. Egg weight was independent of all measures of female size, but was directly and significantly (P = 0.03) correlated with standard flight muscle weight, a relative index of body condition. Egg size was thus a function more of female body condition than size. On average, shell, yolk, and albumen comprised 5.6%, 21.9%, and 72.5%, respectively, of fresh egg weight. Dry albumen and dry shell increased proportionately with fresh egg weight, but dry yolk did not. Total protein, lipid, and energy of fresh eggs all increased proportionately with weight. Comparison of egg composition and standard flight muscle weight of laying females indicated moderate positive, although nonsignificant, correlations between body condition and measures of egg quality, especially lipid content. Based on postegg- laying body composition and nutrient requirements for the production of one egg, it appeared that most females probably could have laid an additional egg almost solely from body reserves. Clutch size thus appears to be independent of body condition

Avian Population Trends Within the Evolving Agricultural Landscape of the Eastern and Central United States

State-level Breeding Bird Survey (1980-1998) and U.S. Department of Agriculture statistics were used to test the hypothesis that changes in agricultural land use within the eastern and central U.S. have driven population trends of grassland and shrub habitat birds over the past two decades. The degree to which population trends differed between grassland and shrub habitats was evaluated with respect to migratory and nesting behavior. Grassland birds declined significantly between 1980 and 1999, but, on average, shrub habitat species did not. Grassland-breeding, long-distance migrants exhibited the strongest negative trends. Most species (78%; n = 63) exhibited at least one significant association between population trends and changes in agricultural land use, and in most, land use explained 25-30% of the variation in population trends among states. Changes in the farmland landscape accounted for more of the interstate variability of population trends of short-distance migrants than of both long-distance migrants and residents, and that variability was greater in grassland than shrub species. Declines in the area of rangeland and cover crops were followed by population declines and increases, respectively, by many species. Increases of land in the Conservation Reserve Program had negative associations with population trends of some shrub species. The results indicate that grassland birds have declined strongly over the past two decades, and that regardless of migratory behavior or nesting habits, avian population trends are linked strongly to changes in agricultural land use within North America

Keck constraints on a varying fine-structure constant: wavelength calibration errors

The Keck telescope's HIRES spectrograph has previously provided evidence for a smaller fine-structure constant, alpha, compared to the current laboratory value, in a sample of 143 quasar absorption systems: da/a=(-0.57+/-0.11)x10^{-5}. This was based on a variety of metal-ion transitions which, if alpha varies, experience different relative velocity shifts. This result is yet to be robustly contradicted, or confirmed, by measurements on other telescopes and spectrographs; it remains crucial to do so. It is also important to consider new possible instrumental systematic effects which may explain the Keck/HIRES results. Griest et al. (2009, arXiv:0904.4725v1) recently identified distortions in the echelle order wavelength scales of HIRES with typical amplitudes +/-250m/s. Here we investigate the effect such distortions may have had on the Keck/HIRES varying alpha results. We demonstrate that they cause a random effect on da/a from absorber to absorber because the systems are at different redshifts, placing the relevant absorption lines at different positions in different echelle orders. The typical magnitude of the effect on da/a is ~0.4x10^{-5} per absorber which, compared to the median error on da/a in the sample, ~1.9x10^{-5}, is relatively small. Consequently, the weighted mean value changes by less than 0.05x10^{-5} if the corrections we calculate are applied. Nevertheless, we urge caution, particularly for analyses aiming to achieve high precision da/a measurements on individual systems or small samples, that a much more detailed understanding of such intra-order distortions and their dependence on observational parameters is important if they are to be avoided or modelled reliably. [Abridged]Comment: 9 pages, 2 figures, 2 tables. Invited contribution to Proc. IAU XXVIIth General Assembly, Joint Discussion 9, "Are the fundamental constants varying with time?". To appear in P. Molaro, E. Vangioni-Flam, eds, Memorie della Societa Astronomica Italiana (MmSAIt), Vol. 80. Complete version of Table 1 available at http://astronomy.swin.edu.au/~mmurphy/pub.htm