Ringed Research Articles

Captures of Northern Saw-whet Owls (Aegolius acadicus) correlate with the lunar cycle during fall migration

ABSTRACT As a small nocturnal migrant, the Northern Saw-whet Owl (Aegolius acadicus) is hypothesized to reduce predation risk by avoiding migration during the full moon. However, small-scale studies have given mixed results on whether there is a relationship between capture rate of Northern Saw-whet Owls and the lunar cycle during fall migration. We used 50 years of data from the U.S. Bird Banding Laboratory to examine capture rates of Northern Saw-whet Owls throughout North America in relation to lunar illumination. A logistic regression of 156,794 fall captures compared to random dates in the fall showed that captures are significantly less likely as lunar illumination increases. Captures at high illumination were 22% less likely than captures on moonless nights during the waning half of the lunar cycle and 41% less likely during the waxing half of the lunar cycle. Modification of the lunar illumination index to correct for the duration of the night that the moon is in the sky gave similar results. Owls...

Sex‐obsessed or just sociable? Non‐copulatory displays in the hamerkop

Sex‐obsessed or just sociable? Non‐copulatory displays in the hamerkop

Cross‐seasonal effects on waterfowl productivity: Implications under climate change

ABSTRACTPrevious efforts to relate winter‐ground precipitation to subsequent reproductive success as measured by the ratio of juveniles to adults in the autumn failed to account for increased vulnerability of juvenile ducks to hunting and uncertainty in the estimated age ratio. Neglecting increased juvenile vulnerability will positively bias the mean productivity estimate, and neglecting increased vulnerability and estimation uncertainty will positively bias the year‐to‐year variance in productivity because raw age ratios are the product of sampling variation, the year‐specific vulnerability, and year‐specific reproductive success. Therefore, we estimated the effects of cumulative winter precipitation in the California Central Valley and the Mississippi Alluvial Valley on pintail (Anas acuta) and mallard (Anas platyrhnchos) reproduction, respectively, using hierarchical Bayesian methods to correct for sampling bias in productivity estimates and observation error in covariates. We applied the model to a hunter‐collected parts survey implemented by the United States Fish and Wildlife Service and band recoveries reported to the United States Geological Survey Bird Banding Laboratory using data from 1961 to 2013. We compared our results to previous estimates that used simple linear regression on uncorrected age ratios from a smaller subset of years in pintail (1961–1985). Like previous analyses, we found large and consistent effects of population size and wetland conditions in prairie Canada on mallard productivity, and large effects of population size and mean latitude of the observed breeding population on pintail productivity. Unlike previous analyses, we report a large amount of uncertainty in the estimated effects of wintering‐ground precipitation on pintail and mallard productivity, with considerable uncertainty in the sign of the estimated main effect, although the posterior medians of precipitation effects were consistent with past studies. We found more consistent estimates in the sign of an interaction effect between population size and precipitation, suggesting that wintering‐ground precipitation has a larger effect in years of high population size, especially for pintail. When we used the estimated effects in a population model to derive a sustainable harvest and population size projection (i.e., a yield curve), there was considerable uncertainty in the effect of increased or decreased wintering‐ground precipitation on sustainable harvest potential and population size. These results suggest that the mechanism of cross‐seasonal effects between winter habitat and reproduction in ducks occurs through a reduction in the strength of density dependence in years of above‐average wintering‐ground precipitation. We suggest additional investigation of the underlying mechanisms and that habitat managers and decision‐makers consider the level of uncertainty in these estimates when attempting to integrate habitat management and harvest management decisions. Collection of annual data on the status of wintering‐ground habitat in a rigorous sampling framework would likely be the most direct way to improve understanding of mechanisms and inform management. © 2016 The Wildlife Society.

Bias in ring‐recovery studies: causes of mortality of little owlsAthene noctuaand implications for population assessment

Recoveries of marked animals hold long‐term, large‐scale information on survival and causes of mortality, but are prone to bias towards dead recoveries and casualties in the range of presence of potential finders. Thus, accounting for circumstance‐related recovery probabilities is crucial in statistical approaches. For the little owl, a species of conservation concern in central Europe, raw ring recoveries suggested a strong human‐related impact on survival. We analysed the proportions of the main causes of death using a large sample of radio‐tracked birds as a reference. We compared ring recoveries in southern Germany collected 1950–2012 (n = 465 dead recoveries of 2007 recoveries of 30 623 ringed birds) with data from a radio‐tracking study in the same region 2009–2012 (n = 177 dead recoveries of 377 tagged individuals). Two assumptions of multi‐state ring recovery modelling were unrealistic. First, not all dispatched rings remained available to potential finders. Instead, 34% of tracked birds were displaced to sites where rings were irretrievable, resulting in biased estimates of recovery probability. Second, the proportions of irretrievable rings were disproportional, with 48% in predated birds and 5% in human‐induced mortality. Consequently, the sample of rings from which recoveries were drawn differed from the sample of dispatched rings. Accounting for these biases in a multi‐state model, we estimated the frequencies of main causes of mortality to 45% for predation, 20% for casualties due to traffic and at buildings and 34% for all other causes. In radio‐tracked birds, predation was even more dominant (76%). Integrating mark–recapture data and telemetry observations allowed detecting and quantifying so far unknown recovery bias and resulted in improved estimates of key population parameters. The demography of little owls likely depends mainly on predator–prey relationships rather than on human‐induced deaths.

A new species of Neoephemera McDunnough, 1925 (Ephemeroptera:Neoephemeridae) from North Carolina and Virginia.

Neoephemera eatoni sp. nov. is described based on nymphs, imagos, and eggs from North Carolina and Virginia, USA. Nymphs of the new species are associated only with hornleaf riverweed (Podostemum ceratophyllum) growing on the surfaces of cobbles and boulders in moderate to swift flows, at a depth of up to one meter. Life stages were associated by laboratory rearing. Nymphs of the new species are distinguished from other Nearctic Neoephemera by the following combination of characters: all legs are short and stout, with overall lengths subequal to each other; tibial and tarsal lengths are subequal on all legs; tarsal claws are sharply curved; anterolateral projections on the pronotum and mesonotum are reduced; and anterosubmedian tubercles are absent from the pronotum. Male and female imagos exhibit unique abdominal maculations; the anterior protuberance of the mesonotum is obovate; and distinct leg banding patterns are absent. Male imagos have the fore tibia at least 2× the length of mid and hind tibiae, and female imagos have all legs subequal in length. Our new species may be most closely related to N. youngi based on imagos of the two species each having a small spine posteromedially on abdominal tergum II and having annulated terminal filaments. An updated key to North American species is provided.

Advanced long-term bird banding and climate data mining in spring confirm passerine population declines for the Northeast Chinese-Russian flyway

The migration of birds is fascinating for humans but it's also a serious environmental monitoring and management issue on a global level. Bird banding using mistnets has been the method of choice for decades worldwide; linking these data with climate data allows to infer on global warming and outlier events. However, good methods to achieve this effectively in time and space for many species are still missing; data for Asia are specifically sparse and often ‘messy’. Here we present a data mining summary information for data from two bird banding stations (Gaofeng and Qingfeng) along the vast Northeast Chinese-Russian flyway. Bird data were collected during spring 2002–2011 with standardized techniques and then linked with related climate data in the banding as well as the wintering sites. This creates a complex data set which is based on a decade and which includes many predictors. This first-time data mining analysis with ‘data cloning’ and machine learning methods (boosted regression trees) shows how to extract the major signals in this unique dataset from highly correlated and interacting predictors. Our results indicate a large-scale warming trend for the flyway, with a start in 2003, and a freezing rain outlier event in 2008; the last years remained on a rather warm level. All evidence along this vast flyway supports major changes, warming trends, habitat losses and consequently strong passerine declines. Presumably human pressures are a major factor either way and we propose to address these problems immediately for betterment if meaningful conservation targets are to be met.

Can acaricide‐impregnated leg bands fitted to female red grouse reduce sheep tick parasitization of chicks and increase chick survival?

In parts of northern England, North Wales and the Scottish Highlands, increasing numbers of sheep ticks Ixodes ricinus (Ixodida: Ixodidae), and the louping ill virus they can carry, are considered to be important factors that reduce red grouse Lagopus lagopus scotica productivity. The present study tested this hypothesis by fitting adult female grouse with leg bands impregnated with the acaricide cypermethrin to experimentally control ticks on their chicks on two managed grouse moors in northeast Scotland. The chicks of females fitted with acaricide leg bands showed reduced tick infestations and improved survival in one of the two study years, relative to chicks of control females. Acaricide leg bands constitute a potential management technique that may be adopted by grouse moor managers in circumstances of high tick infestations on grouse chicks.

Effect of the Porosity Ran ge and its Nature on Mechanical Properties of Magnesium Alloys Mg-Al-Zn

The possibilities of porosity adjustment in alloys of the Mg-Al-Zn system obtained by melting under a layer of flux were studied. The elements that significantly increase corrosion resistance and heat resistance, and improve mechanical strength and technological characteristics were chosen as doping components. Measurements showed that the range of porosity varied between 5.9 and 14.8%, and the relationship<br />between porosity and strength of alloys was defined for the first time for this range. For an alloy with porosity of 14.8%, the percentage of open pores was 12.8% while the percentage of closed pores was 2%. Micro-hardness of alloys with the given porosity was 661 MPa after casting, 876 MPa after homogenizing annealing and 897 MPa after artificial aging. The tensile strength was 235 MPa. Analysis identified that the main cause of porosity was catching atoms of hydrogen from atmosphere by molten alloys during melting, casting and liquation. In order to reduce the percentage of porosity alloys were doped by metal manganese, liquid metal was processed by calcium and hexachloroethane, and casting form was treated by boron nitride. These manipulations resulted in reduction of samples porosity up to 5.9%, increase of tensile strength up to 240 MPa. Open porosity was 4.5%, while closed porosity was 1.4%. At the same time micro-hardness of cast samples was 867 MPa, 903 MPa after homogenization annealing and 961 MPa after artificial aging. Further reduction of porosity and increasing of magnesium alloys strength is possible with the use of inert gases or vacuum melting. Samples porosity can be increased by more than 14.8% with the help of melting in the hydrogen containing atmosphere.

The EURING Data Bank – a critical tool for continental-scale studies of marked birds

ABSTRACTThe European Union for Bird Ringing (EURING) coordinates bird ringing at a continental scale and operates the EURING Data Bank (EDB) to facilitate large-scale analyses of movements and demography. The EDB contains over 10 million individual encounter records which are summarised on a publicly available website, the EDB index. EURING welcomes applications to analyse these data. Ring-recovery data from the EDB contribute to research on many ecological issues, particularly migration and movements, hunting, mortality causes, disease transmission, population dynamics and dispersal. Recent developments will facilitate the incorporation of comprehensive sets of first-encounter records and local recaptures which are essential for robust quantitative studies of population dynamics and movements. Furthermore, the recent inclusion of fields for moult, measurements and weights within the EURING code will facilitate novel research at a European scale. We expect increasing use of the EDB for quantitative studies of avian demography and movements with high applied value. Wherever possible, this research should also incorporate complementary ecological information. EURING’s immediate priority is the production of a European Migration Atlas that would provide an up-to-date synthesis of the movements of European bird populations, with many direct implications for their conservation.

Impact of weather conditions on ringing intensity in Suichuan avian passage, China

Suichuan is the second largest avian migration passage in China, while studies about local migration situation were rarely conducted. In this study, it aimed to provide the primary understanding of migration in Suichuan. The scale and diversity of migrants were analyzed. Moreover, the relationship between weather conditions including wind and rainfall and ringing intensity were also explored. Based on the field collected data from 2005 to 2010, dominant migrants in Suichuan were Ciconiiformes and Passeriformes, followed by Gruiformes, and the diversity of migrant species peaked in 2007. Correlations of bird ringing intensity with wind speed and rainfall were derived through a univariate analysis. Different groups of migrants shared different correlation patterns with each weather condition. Ringing intensity of small size Passeriformes was most easily affected by the adverse weather conditions (daily rainfall ≥15 mm or wind speed >2.5 ms−1); Gruiformes shared significant correlations with wind speeds 2.5 ms−1. Multiple linear regression analysis confirmed that higher rainfall and stronger wind hampered total ringing intensity and these two predictors together could explain 79 % of the variation of total ringing intensity. Moreover, east wind was related to higher ringing intensity, especially for the groups of Ciconiiformes and others. The result of this exploratory study has important implications for assessing the impact of meteorological variables, such as wind and rain on migratory behavior in Suichuan.

Hitchhikers’ guide to analysing bird ringing data

Abstract This paper is the second part of our bird ringing data analyses series (Harnos et al. 2015a) in which we continue to focus on exploring data using the R software. We give a short description of data distributions and the measures of data spread and explain how to obtain basic descriptive statistics. We show how to detect and select one and two dimensional outliers and explain how to treat these in case of avian ringing data.

Breeding of White-tailed Tropicbirds (Phaethon lepturus) in the western South Atlantic.

Basic information on natural history is crucial for assessing the viability of populations, but is often lacking for many species of conservation concern. One such species is the White-tailed Tropicbird, Phaethon lepturus (Mathews, 1915). Here, we address this shortfall by providing detailed information on reproductive biology, distribution and threats on the Fernando de Noronha archipelago, Brazil - the largest colony of P. lepturus in the South Atlantic. We assessed reproduction from August 2011 to January 2012 by monitoring tropicbird nests and their contents. A population estimate was obtained through a combination of active searches for nests and by census at sea between 2010 and 2012. Breeding success was calculated by traditional methods. The growth curve of chicks and life table were also calculated. Additional information on nest and mate fidelity and on age of breeding birds was obtained from the banded birds. Our results indicate that the unusual nest form (limestone pinnacles) and predation by crabs may be responsible for the observed patterns of hatching and fledging success. Although the Fernando de Noronha population appears to be stable (at between 100-300 birds), a long term monitoring program would be desirable to assess fluctuations in this globally important population. Conservation strategies should focus on controlling predation by land crabs and tegu lizards.

Identification of migratory bird flyways in North America using community detection on biological networks.

Migratory behavior of waterfowl populations in North America has traditionally been broadly characterized by four north-south flyways, and these flyways have been central to the management of waterfowl populations for more than 80 yr. However, previous flyway characterizations are not easily updated with current bird movement data and fail to provide assessments of the importance of specific geographical regions to the identification of flyways. Here, we developed a network model of migratory movement for four waterfowl species, Mallard (Anas platyrhnchos), Northern Pintail (A. acuta), American Green-winged Teal (A. carolinensis), and Canada Goose (Branta canadensis), in North America, using bird band and recovery data. We then identified migratory flyways using a community detection algorithm and characterized the importance of smaller geographic regions in identifying flyways using a novel metric, the consolidation factor. We identified four main flyways for Mallards, Northern Pintails, and American Green-winged Teal, with the flyway identification in Canada Geese exhibiting higher complexity. For Mallards, flyways were relatively consistent through time. However, consolidation factors revealed that for Mallards and Green-winged Teal, the presumptive Mississippi flyway was potentially a zone of high mixing between other flyways. Our results demonstrate that the network approach provides a robust method for flyway identification that is widely applicable given the relatively minimal data requirements and is easily updated with future movement data to reflect changes in flyway definitions and management goals.

Age and sex determination of Mallards Anas platyrhynchos in autumn

Male and female mallards Anas platyrhynchos are easily told apart, whereas ageing is problematic, due to individual timing of moult and lack of easily defined age criteria. From examination and photographic documentation of mallards caught at Ottenby Bird Observatory (56°12′N, 16°24′E), we describe nine characters of plumage and bare parts to be used for ageing in autumn. The reliability of these characters was tested by letting experienced bird ringers determine putative age of birds from photos. Age determination from any single character proved to be uncertain, as correctly assigned mallard photos of each character was in the range of 51–85% for males and 48–89% for females. For both sexes, the lowest figure represented post-humerals and the highest represented tertials. Rectrices, tertial coverts, and greater coverts had high scores (71–85%). Using all characters, 91% of the males and 95% of the females were correctly aged. As young mallards, with the progress of pre-breeding moult (completed from October onwards), acquire tail and tertials identical to adults, untypical individuals are better not assigned to an age category.

Retrospective Study Of Expert Examination Performed By The Brazilian Federal Police In Investigations Of Wildlife Crimes, 2013-2014.

One of the main demands for veterinary medical experts is the forensic investigation of crimes against wildlife. In Brazil, most of these crimes are related to the trafficking of wild animals, whose conducts involve the capture, transport and illegal trade of specimens. All these activities also involve various forms of animal mistreatment. This article aims to present the main types of expert examinations used in investigations of wildlife crimes through a retrospective study of records kept by the Criminalistic System of the Brazilian Federal Police in the years 2013 and 2014. The increase in the number of examinations performed in 2014, compared to the year 2013 (86.15%), was mainly focused on identification, mistreatment and investigation of bird ring forgery, reaffirming the importance of these tests in the casuistry of the Federal Police.

Effects of Researcher-Induced Disturbance on American Kestrels Breeding in Nest Boxes in Northwestern New Jersey

Abstract Nest boxes for American Kestrels (Falco sparverius) may alleviate local nest site limitation, but there is concern that periodically opening nest boxes or handling adults may negatively affect nesting success. I monitored 536 kestrel breeding attempts (≥1 egg laid) in about 100 nest boxes in northwestern New Jersey, 1995–2012. To study return rates, I opportunistically captured adults in nest boxes and marked them with U.S.G.S. leg bands and patagial tags. To examine possible effects of this disturbance, I compared nesting success (≥1 nestling surviving to banding age) of marked and unmarked adults. Nesting success was 67% for 270 unmarked pairs, 76% for 25 pairs with only the male marked, 82% for 206 pairs with only the female marked, and 91% for 35 pairs with both adults marked. This significant difference likely reflects differences in the probability of capture: successful attempts last longer and successful parents may be more attentive. To control for these correlations, I examined attempts...

Retention of Riveted Aluminum Leg Bands by Wild Turkeys

Abstract In order for mark–recapture models to provide unbiased estimates of population parameters, it is critical that uniquely identifying tags or marks are not lost. We double-banded male and female wild turkeys with aluminum rivet bands and estimated the probability that a bird would be recovered with both bands <1–225 wk since banding (mean = 51.2 wk, SD = 44.0). We found that 100% of females (n = 37) were recovered with both bands. For males, we recovered 6 of 188 turkeys missing a rivet band for a retention probability of 0.984 (95% CI = 0.96–0.99). If male turkeys are double-banded with rivet bands the probability of recovering a turkey without any marks is <0.001. We failed to detect a change in band retention over time or differences between adults and juveniles. Given the low cost and high retention rates of rivet aluminum bands, we believe they are an effective marking technique for wild turkeys and, for most studies, will minimize any concern about the assumption that marks are not lost.

AVES MIGRATORIAS NEOTROPICALES RECAPTURADAS EN ALGUNAS LOCALIDADES DE LOS DEPARTAMENTOS DE ATLÁNTICO Y MAGDALENA, CARIBE COLOMBIANO

Information obtained from the recoveries of banded birds has historically been used to deduce their migratory routes and other key aspects of their life histories. This paper analyses information on Neotropical migratory species recaptured in the Colombian provinces of Atlántico and Magdalena between 1923 and 2011, using data obtained from the U. S. Bird Banding Laboratory. In this area 707 individuals of 14 species of waterbirds were encountered, among which were blue-winged teal (Anas discors) and royal tern (Thalasseus maximus) with the largest number of encountered individuals, as well as species with few records in Colombia: American wigeon (Anas americana), Northern pintail (Anas acuta), and roseate tern (Sterna dougalli). This analysis contributes to knowledge about the distribution of several species occurring in the country and assesses their migratory status; for instance, we determined that Eudocimus albus has both migratory and resident populations in Colombia. This paper attempts to promote the use of existing data on recaptured birds, and to bring attention to the fact that people who inhabit the study area are unaware of the bird banding goals, which has resulted in hunting of banded birds, illegal pet trade, and removal of the bands from birds.

Managing Raptor-Aircraft Collisions on a Grand Scale: Summary of a Wildlife Services Raptor Relocation Program

Author(s): Schafer, Laurence M.; Washburn, Brian E. | Abstract: Bird-aircraft collisions (bird strikes) pose a serious safety risk to aircraft. Raptors (i.e., hawks and owls) are one of the most frequently struck guild of birds within North America. Integrated wildlife damage management programs combine a variety of non-lethal and lethal management tools to reduce the presence and duration of raptors at airports. Live-capture and translocation away from an airport is a commonly used method to reduce the risk of raptor-aircraft collisions. In 2007, USDA APHIS Wildlife Services (WS) developed an airport program-specific plastic leg band (i.e., black with yellow alpha-numerics) for use in operational raptor management activities by the agency at airports. As part of this nation-wide effort, WS airport biologists live-captured, marked with auxiliary markers (i.e., project-specific leg band), and conducted over 3,900 raptor translocations from airports and military bases located in 16 states during January 2008-May, 2015. This represents a large portion of the raptors that were managed using this non-lethal method by WS during these years. Not unexpectedly, raptor translocation efforts and the raptor species managed varied among geographic regions/states and at specific airport locations due to a variety of logistical factors. Fifteen different raptor species were marked and translocated during this effort. Red-tailed hawks, American kestrels, and great horned owls accounted for 58%, 14%, and 6% of marked/translocated birds, respectively. Although research is needed to better understand and increase the efficacy of such management efforts, this non-lethal method of reducing the presence of individual raptors at airports will be an important component of future wildlife damage mitigation programs.

Population Dynamics of the Feral Pigeon in the Central Business District of Butte, Montana

The purpose of this study was to gather information on the feral pigeon population living in the central business district (CBD) of Butte, MT. Pigeons in the CBD have historically been part of the urban landscape and have contributed to local biodiversity. We report on an aspect of a larger study that was initiated to address complaints from business owners concerning damage caused by pigeons. To better understand feral pigeon population dynamics, we used live trapping, marking with leg bands, and survey transects to study the pigeons’ distribution, habitat selection, and dispersal. Our results thus far indicate minimal dispersal between colonies. Two individuals have shown dispersal movements of up to 6.1 km from the tagging site. Transect surveys revealed an average of 173.3 birds present, with a maximum count of 254 and minimum of 101.