Wing size but not wing shape is related to migratory behavior in a soaring bird

Both wing size and wing shape affect the flight abilities of birds. Intra and inter‐specific studies have revealed a pattern where high aspect ratio and low wing loading favour migratory behaviour. This, however, have not been studied in soaring migrants. We assessed the relationship between the wing size and shape and the characteristics of the migratory habits of the turkey vulture Cathartes aura, an obligate soaring migrant. We compared wing size and shape with migration strategy among three fully migratory, one partially migratory and one non‐migratory (resident) population distributed across the American continent. We calculated the aspect ratio and wing loading using wing tracings to characterize the wing morphology. We used satellite‐tracking data from the migratory populations to calculate distance, duration, speed and altitude during migration. Wing loading, but not aspect ratio, differed among the populations, segregating the resident population from the completely migratory ones. Unlike what has been reported in species using flapping flight during migration, the migratory flight parameters of turkey vultures were not related to the aspect ratio. By contrast, wing loading was related to most flight parameters. Birds with lower wing loading flew farther, faster, and higher during their longer journeys. Our results suggest that wing morphology in this soaring species enables lower‐cost flight, through low wing‐loading, and that differences in the relative sizes of wings may increase extra savings during migration. The possibility that wing shape is influenced by foraging as well as migratory flight is discussed. We conclude that flight efficiency may be improved through different morphological adaptations in birds with different flight mechanisms.     

Geographic patterns of species richness of diurnal raptors in Venezuela

Knowledge of a species’ geographic distribution is crucial to assessing its vulnerability. It is also important to know if protected areas provide effective protection for raptor species. Here, we examine the species richness (S) patterns, factors predicting S and the effectiveness of protected areas (EPA) in the conservation of diurnal raptors in Venezuela. We modeled geographic distributions (SDM) of 64 raptor species using ecological niche models. Nine climatic and seven landscape metrics were used as environmental predictors. SDM were stacked to examine S and predictors of S were investigated using regression models. This study evaluated S patterns in the 13 bioregions defined for Venezuela. A gap analysis was performed to evaluate the EPA in the conservation of raptor diversity. Forty species showed a continuous distribution, whereas as disjunct distributions were observed in 24 species. Species richness differed among bioregions; six pairwise compared bioregions did not show differences. Guyana Massif and the mountains of northern Venezuela had the highest species richness. Landscape features, specifically canopy height, land cover and terrain slope explained most of the species richness. Environmental heterogeneity affected the distribution of S and is therefore important in conservation planning for Neotropical raptors. Responses from environmental variables used to predict S were scale dependent; it is necessary to standardize methods/experimental design to study the biogeography of raptors. Priority-setting for the conservation of raptors in Venezuela must consider restricted range species, even if they are not threatened. A new territorial ordering is urgent to improve the protection of this group of birds.     

Purification of proline-rich proteins from parotid glands of isoproterenol-treated rats.

Prolonged isoproterenol treatment of rats is known to cause hypertrophy and hyperplasia of the parotid glands. Our results show that a dramatic increase in the synthesis or accumulation in the parotid glands of a series of proteins rich in proline also occurs with isoproterenol treatment. After 10 days of treatment (5 mg of isoproterenol/day) these proline-rich proteins (PRPs) comprise more than 50% of the total soluble proteins in parotid gland homogenates. The PRPs are rapidly labeled in vivo by a single intraperitoneal injection of [3H]proline with maximum incorporation occurring at about 3. More than 90% of the [3h]proline found in parotid gland homogenates is incorporated into PRPs with less than 1% of the radioactivity in alpha-amylase. Tritium incorporated into PRPs was isolated as [3H]proline after acid hydrolysis. One acidic and six basic 3H-labeled PRPs were isolated from the 100,000 x g supernatant fraction of parotid gland homogenates by Sephadex G-100 and ion exchange chromatography. The six basic proteins accounted for about 90% of the total PRPs isolated.     

Wading bird use of established and newly created reactor cooling reservoirs at the Savannah River Site,near Aiken,South Carolina,USA

We compared wading bird use of a newly created 405-ha reactor cooling reservoir (L-Lake) at the Savannah River Site, near Aiken, South Carolina, with that of two similar > 25-year-old reservoirs (1130-ha Par Pond and 87-ha Pond B) at the same site. L-Lake was constructed in 1984–1985 and filled in late 1985. Approximately 25% of the shoreline of L-Lake was planted with lacustrine vegetation in early 1987 in an attempt to speed the establishment of a self-sustaining balanced biological community (BBC) at the reservoir. Even so, during the course of our studies, L-Lake had considerably less wetland vegetation, especially floating-leaved species such as yellow nelumbo (Nelumbo lutea), than did either of the two older reservoirs.Sixty-three surveys of the avian communities using the three reservoirs were conducted between fall of 1987 and summer of 1989. These surveys indicated that (1) at least seven species of wading birds (order: Ciconiiformes) used L-Lake, (2) wading bird density was higher at L-Lake than at the other two reservoirs, (3) wading birds represented a higher proportion of the total avian community at L-Lake than at the other two, older reservoirs, and (4) wading birds at L-Lake used planted portions of the shoreline more than unplanted portions. We suggest that the inter-reservoir differences we observed represent a trophic upsurge (sensu O'Brien, 1990) resulting from the increased availability of fishes at L-Lake compared with the two older reservoirs.Work was performed at the University of Georgia's Savannah River Ecology Laboratory, Aiken, South Carolina 29802.     

Winter diet of striated caracara Phalcoboenus australis (Aves, Polyborinae) at a farm settlement on the Falkland Islands

Striated caracaras occur only on the Falkland Islands and the outer islands of southern Chile and Argentina. In summer, the species associates with seabirds and seals and depends heavily upon them for food. The winter diet is less well understood. We studied the diet of 90–130 mainly juvenile and sub-adult striated caracaras overwintering at a farm on Saunders Island, Falkland Islands, in mid-winter (July–August) 2011. Direct observations of feeding and regurgitation pellets collected at a roost indicate that the winter diet of the striated caracaras at the site is mainly native geese, beetles and other invertebrates, and the carcasses of domestic sheep. This study illustrates seasonal shifts in the diet of this near-threatened South Atlantic endemic and suggests an important nutritional link between juvenile and subadult caracara survival in winter and traditional human activities at sheep farms.     

Prevalence of west Nile virus antibodies in a breeding population of American Kestrels (Falco sparverius) in Pennsylvania

West Nile virus (WNV) has been identified in nearly 300 species of wild birds, including raptors, in North America since its introduction in New York City in 1999. American Kestrels (Falco sparverius) are susceptible to WNV infection, and the numbers of these birds have declined along the Atlantic coast in recent years. We examined the population biology and WNV exposure of kestrels breeding in the area surrounding Hawk Mountain Sanctuary in Kempton, Pennsylvania, USA. The reproductive biology of kestrels in this area was studied from 1992 until 2004. The number of kestrels breeding in nestboxes in 2004 was only 44% of the 6-yr mean observed prior to 1999. During the 2004 nesting season (study period: 8 June through 22 July 2004), adult kestrels were trapped near the site of their nestboxes. Blood samples were obtained, and serum antibodies specific to WNV were quantified using a plaque reduction neutralization test. Of 22 birds tested, 21 exhibited serum antibodies to WNV, suggesting that most (95%) of the adult kestrels in the population had been exposed to WNV.     

Heat loss and site-dependent fecundity in chinstrap penguins (Pygoscelis antarctica)

We study the effects of heat loss and nest site quality on fecundity in a chinstrap penguin (Pygoscelis antarctica) colony on Deception Island, Antarctica. During the austral summers of 1990–1991, 1993–1994, and 1995–1996, 441 randomly selected nests were analyzed. Penguins breeding in the center of subcolonies hatched significantly earlier and had larger broods and than those nesting near or at the edge of the subcolonies. These differences, however, were significantly affected by interaction between year and nest location, being highly significant in colder years, when peripheral nests produce fewer young. Analysis of the rate of heat loss showed that penguins breeding at the edge of subcolonies lost heat twice as rapidly as those breeding in the interior of the subcolony. In a re-occupation experiment, evacuated center nests were re-occupied almost ten times as rapidly as edge nests. An analysis of mean fecundity in the period 1991–1996 and mean wind chill suggested that most of the variability in fecundity among years was related to differences in the rate of heat loss. Subcolonies tend to be as circular as possible, thereby decreasing the proportion of edge nests as the size of subcolony increases. Our results support the site-dependent fecundity hypothesis.     

Effects of trypsin and protein modification on the renal transporter ofp-aminohippurate

Summary Basal-lateral membranous vesicles prepared from rabbit renal cortex exhibited Mg²⁺-stimulated, probenecid-inhibitable transport ofp-aminohippurate (PAH). This uptake could be completely eliminated by incubating the membranes with trypsin at a weight ratio of 1700 (trypsin/membrane protein). The loss of PAH uptake activity occurred in two stages. Over the first ten minutes of the vesicles' exposure to trypsin, there was a nearly linear loss, with respect to time, of about 80% of the PAH uptake activity. The remaining 20% of activity was resistant to further trypsin digestion for the next ten minutes, but by twenty-five minutes a total inactivation of the uptake activity occurred. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of normal and trypsin-treated vesicles showed very little degradation of proteins. However, two minor polypeptides (M_r-410,000 and 388,000) were degraded during the first ten minutes of the membranes' exposure to trypsin. After twenty minutes of exposure, two other poypeptides (M_r=94,500 and 87,500) were degraded. Chymotrypsin and clostripain also caused a loss of PAH transport activity. However, compared to the effects of trypsin, the effects of these two proteases were less complete, slower in onset, and for clostripain, a much higher concentration of enzyme was required. Other functions or properties of the vesicles including morphological appearance, degree of vesiculation, glucose space or Na⁺-dependentl-glutamate transport and Na⁺, K⁺-ATPase activity were not altered by the concentration of trypsin which abolished 80% of the transport of PAH. Thus, it is possible that one or more of the degraded polypeptides detected by polyacrylamide gel electrophoresis comprises the PAH transporter. Furthermore, modification of the vesicles with phenylglyoxal led to a 38% loss of PAH uptake activity. This suggests that arginine residues may play an important role in the transport system.     

Unusual clockwise loop migration lengthens travel distances and increases potential risks for a central Asian,long distance,trans-equatorial migrant,the Red-footed Falcon Falco vespertinus

Capsule: Red-footed Falcons Falco vespertinus migrating from northern Kazakhstan proceed west before heading south to Africa; their northbound travel follows a different route with passage close to shooting hotspots in the Mediterranean.

Aim: To use tracking and ringing data to document for the first time the migration of globally threatened Red-footed Falcons from northern Kazakhstan.

Methods: Light-level geolocators were deployed on breeding adults in Kazakhstan and recovered one year later. Ringing and observational data from more than 100 years of Russian-language and other literature were summarized and mapped alongside the geolocator data.

Results: Geolocator, ringing and observational data together demonstrate that Red-footed Falcons from northern Kazakhstan have a clockwise loop migration that begins with a long and unusual westward trek around eastern Europe’s large inland seas before continuing to extreme southern Africa. Return migration is farther west and requires crossing two major migratory barriers: the Sahara and the Mediterranean.

Conclusion: The loop migration we describe requires an extensive longitudinal movement, exposes central Asian Red-footed Falcons to multiple desert, mountain and marine crossings, and, at outbound and return Mediterranean bottlenecks, crosses sites where raptor shooting is common.