Journal of Ornithology

Cory’s Shearwater, Calonectris diomedea, is a pelagic seabird that winters in the waters off the state of Rio Grande do Sul in southern Brazil. Elsewhere, its diet is comprised mostly of fish and cephalopods, but dietary details out of the breeding season are unknown. The present study analysed the diet of Cory’s Shearwater along the coast of Rio Grande do Sul based on the stomach contents of 185 birds found dead during beach surveys between July 1997 and July 1998. Food items were classified taxonomically and non-food items were categorized. The taxa identified included the cephalopods Argonauta nodosa and Histioteuthis sp. and the fish Paralonchurus brasiliensis, Porichthys porosissimus, and Prionotus punctatus. Cephalopods were present in 97% of stomachs and fish in 33% of stomachs. Synthetic materials were found in 81% of stomachs. Our data corroborate the general ideas of Procellariiform diet during migration. The high amount of synthetic materials indicates the pollution of the marine environments of southern Brazil and we call attention to this situation.

Leg-mounted loggers are increasingly used in seabird activity studies, but few studies have validated the information obtained about bird behaviour with independent data. Using Brünnich’s Guillemot Uria lomvia as a study species, we show by comparing interpretations of time–depth recorder (TDR) data with visual observations that activity budgets inferred from leg-mounted TDRs provide reliable information on colony attendance, and validate information on flight time by comparing periods interpreted as flight based on TDR data with periods interpreted as flight based on GPS speed information. Yet, special attention is needed because auks resting at sea occasionally withdraw one leg and/or foot into the plumage (leg-in-plumage). During this behaviour, the TDR may be warm and dry, potentially leading to spurious identification of colony visits. In our case study, spurious identification of colony visits would have resulted in mean trip duration being underestimated by a factor of 4, and number of trips being correspondingly overestimated. We therefore urge great care when deriving activity budgets from leg-mounted TDRs, but nonetheless recommend using leg-mounted TDRs to infer activity budgets from diving seabirds, particularly for longer deployments.

West Nile virus (WNV) is an emerging Flavivirus dispersing throughout the American continent. It has emerged in the United States as an important medical and veterinary pathogen. It was introduced into Argentina late in 2004 with reported activity in human, wild birds and equines. Field evidence supports the hypothesis of an enzootic transmission cycle between free ranging birds and mosquitoes. The aim of this research was to analyze the role of autochthonous birds as maintenance hosts. Bay-Winged Cowbirds, Picui Ground Doves and Shiny Cowbirds were subcutaneously inoculated with an Argentinean isolate of WNV. Bay-Winged and Shiny Cowbirds developed relatively low mean peak viremias (102.7 and 103.5 PFU/mL serum, respectively). Picui Ground Doves had the highest peak viremia titers of the longest duration [104.8 log PFU/mL serum (range 102.9–6.2; 4–5 days duration)]. No mortality was observed during the study. The reservoir competence index for each species suggests that an infected Picui Ground Dove leads to ten times more infectious mosquitoes than one infected Shiny Cowbird, and that Bay-Winged Cowbird do not represent a source of infectious virus for mosquito vectors. This is the first study carried out in the region regarding the avian host of WNV in Argentina. However, additional studies, including seroprevalence and reservoir competence of resident birds as well as vector competence, are needed to shed light on the ecology of this pathogen in Argentina.

Two hundred reels of 16-mm film, containing records of a variety of behavior patterns, mostly of dabbling ducks and geese, were discovered in the spring of 2010 in the attic of the Lorenz mansion in Altenberg––original footage, most of them taken by Konrad Lorenz himself, between 1950 and 1958 at his research station in Buldern (Westphalia, Germany) and at the Severn Wildfowl Trust in Slimbridge [Great Britain (now The Wildfowl and Wetlands Trust)]. These films are now available for further analysis at the Konrad Lorenz Institute for Evolution and Cognition Research, Altenberg Austria.

We quantified nocturnal vocal behaviour in a North American temperate mixed-forest community using automated recording. We recorded for 2–4 nights at 32 locations and identified 18 species singing at dawn or dusk. Of those 18 species, only two sang at night (White-throated Sparrow, Zonotrichia albicollis, and Ovenbird, Seiurus aurocapilla). We show that automated recording is a useful tool for studying nocturnal vocalisations.

When early breeding is advantageous, migrants underway to the breeding areas may be time stressed. The timing of sequential events such as migration and breeding is expected to be correlated because of a “domino effect”, and would be of particular biological importance if timings are repeatable within individuals between years. We studied a colour-marked population of Black-tailed Godwits Limosa l. limosa both on staging areas in Portugal and on breeding areas in The Netherlands. For each individual, we measured the timing of the staging period, the arrival date on the breeding area and the egg laying date. We measured average egg volume as a measure of reproductive investment. The date of departure from the staging areas, the arrival date on the breeding areas, and the egg laying date were repeatable among years in individual Black-tailed Godwits. The arrival dates of paired males and females and the average annual male and female arrival dates were correlated. The dates of departure from Portugal, arrival in The Netherlands, and egg laying were not correlated. Earlier clutches had larger eggs than late clutches. If the length of the individually available pre-laying period is accounted for, early arriving birds spent more time on the breeding grounds before laying than late arriving birds. The repeatability of the itineraries and the correlation between arrival timing of males and females are consistent with observations in other migrants. Despite evidence for early breeding being advantageous, we found no evidence of a “domino effect”.