Peak shift in mate preference learning can be a driver of rapid repeated speciation. Therefore, clades that have undergone recent adaptive radiations are predicted to show biased learning of signals from the opposite sex. The estrildid finches are one such clade. In species including the Zebra Finch Taeniopygia guttata and the Bengalese Finch Lonchura striata var. domestica, females choose mates in part based on their songs. Consistent with theory, female Zebra Finches show peak shift in their learned response to male song characteristics. We used operant conditioning to train female Bengalese Finches to respond to songs with trills of one length and to ignore songs with trills of another length. Then, we exposed those females to songs with a range of trill lengths, and we observed their responses. We found that at least some Bengalese Finches also show behaviour consistent with peak shift in their response to male songs. Moreover, females evaluated songs relative to other songs they had recently heard. Our results suggest that females respond to male sexual signals with bias in multiple species in the rapidly speciating estrildid clade.
The Hooded Crane Grus monacha remains the least known crane species in terms of its breeding range. Since 1985, typical wetlands meeting the characteristics of the typical Hooded Crane habitat have been surveyed between 56° and 66°N and between 108° and 136°E. Within the Lena River Basin, well-defined extensive breeding grounds of the Hooded Crane have been observed in the middle Aldan River Basin. Surveys of representative swampy headwaters, river reaches, and large watershed depressions, have revealed no other similar breeding grounds within the rest of the Lena River Basin, including areas attributed to the only known breeding grounds outside Manchuria. Within the extent of occurrence in the Lena River Basin and adjoining areas of the Olenyek, Khatanga and Yenisei river basins, breeding Hooded Cranes are presumably highly scattered. Solitary pairs are likely to breed hundreds of kilometers apart. Based on the distribution of wetlands, breeding grounds comparable to the middle Aldan River may occur in the basins of the upper Vilyui and the adjoining Moero and Kotui rivers. Evidence suggests that reports from local people are mostly plausible and consistent with maps and satellite images showing wetland habitat similar to that used by the Hooded Crane. Therefore, in the absence of direct data, the reports of the occurrence/nesting of Hooded Cranes beyond the Arctic Circle, particularly in the Olenyek River Basin quoted by Andreev (1974), should be given credence when delineating the breeding range. The region, including the Lena River Basin is too vast and difficult of access for aerial surveys to be practical. Tracking, based on navigation satellite systems, rather than stepwise ground surveys, is the only practical method for obtaining significant information over a short period of time.
Maintaining biological diversity is an important objective at Chitwan National Park (CNP), the most visited national park in Nepal. Given human uses and manipulations of forests both in and around CNP, developing forest management guidelines that can both support human use of trees and sustain the biological diversity of the forests is a high priority. In February 2009 we measured bird communities with point counts, woodpecker abundance with playback, and collected vegetation data in Sal Shorea robusta and riverine forests in CHP and a nearby community forest to provide basic data on bird-habitat associations with an emphasis on woodpeckers. Riverine forest had over twice the density of trees per ha (many small trees), higher tree species richness, and greater basal area than Sal forest. Sal forest had more large trees than riverine forest. We detected 71 bird species during the point counts in the study forests, 18 more during playback sessions, and an additional 12 species that were more associated with adjacent habitats (e.g., wetlands or flying overhead) for a total of 101 species. Among resident species, 31% were primary or secondary tree-cavity nesters. On average for point counts, we detected 29.5 bird species (2.2 woodpeckers) on transects located in riverine forest and 23.3 bird species (1.8 woodpeckers) in Sal forests, but the difference was not statistically significant. While riverine forest had several commonly occurring species not detected in Sal forest, the opposite was not the case. The regression of woodpecker species richness against large tree density in both Sal and riverine forests was positive, but not statistically significant. As a method of sampling woodpeckers, playback resulted in approximately twice the number of individuals and species compared to detection from point counts.
Changes in the timing of bird migration in spring and autumn in a coastal forest near the city of Niigata, central Honshu, Japan, were analyzed based on 27 years of bird-banding records. Half of the bird species studied, including all migratory types except residents, arrived or departed significantly earlier in spring due to an increase in spring temperatures. The rate of change we observed in spring migration timing due to changes in temperature was identical to or slightly greater than those reported in studies from other countries. The spring arrival of the Narcissus Flycatcher Ficedula narcissina and the Japanese Thrush Turdus cardis, both long-distance summer migrants to the nearby mountains, became earlier (advanced), however, for reasons that remained unclear. Median capture date in autumn was significantly associated with year for five species. Of these, the median capture date of the Japanese White-eye Zosterops japonicus, a resident and wandering bird, and the Black-faced Bunting Emberiza spodocephala, a wandering bird, advanced annually, while for the Japanese Robin Luscinia akahige and two other species (all long-distance migrants), it was delayed. We hypothesize that forest succession from a simple pine forest to a mixed forest with well-developed sub-canopy and shrub layers may have strongly influenced the Japanese White-eye and the Black-faced Bunting due to changes in population structure in the study area, resulting in an earlier median autumn capture date. Forest succession may also have influenced the Japanese Robin's food resources, enabling it to stay longer in the study area and resulting in a delay in autumn departure date. Thus, changes in bird migration timing differ according to different environmental factors in spring and autumn.
White-rumped Vulture Gyps bengalensis colonies are expanding in some areas of their range after a catastrophic decline, yet in other areas population status and ecology remain poorly known. In the current study, we documented the first-ever monitoring of population size and nesting activity of the White-rumped Vulture using the road transect method in Kotli District, in Azad Jammu and Kashmir. Covering a 9.09 km road transect we found nine colonies, six of which had a total of 52 active nests (a mean of 5.8±5.6 nests per colony). The nine colonies contained a population of 191 vultures (a minimum of n=7, to a maximum of n=50 with a mean of 21.2±15 individuals per colony). Nests were on Chir Pine trees Pinus roxburghii at an average height of 20.8±1.6 meters from the ground. Most of the nests were near running water sources and roads. Vultures were found at waste from slaughterhouses, livestock carcasses, road-killed wildlife and street dogs, which appear to be their main sources of food. Forest fire could be detrimental to the species' population. Monitoring on an annual basis is needed in order to understand the population trend of the White-rumped Vultures in the area.
Carcass persistence rates strongly affect estimation of avian fatalities resulting from collisions with wind turbines. Our aim was to compare bird carcass persistence rates based on trials during different seasons at wind farms where the ground was snow covered in winter. Carcass persistence was found to be considerably shorter during late winter than during summer/autumn, and was considered to result from food shortages for terrestrial vertebrate scavengers during winter, and the higher visibility of carcasses resting on snow-covered ground in late winter. It is critical to represent carcass persistence rates in different seasons at wind farms.
We examined the breeding success of Lesser Kestrels Falco naumanni in Ikh Nart Nature Reserve, a semi-desert zone in southeast Mongolian. We found that the mean number of nests per colony was 7.4. Lesser Kestrels laid eggs between 24 May and 2 June each year. Mean clutch size was 4.0±0.7 SE, with a mean incubation period of 28±2 SE days. We recorded an overall hatching success rate of 84.2% and overall fledgling success rate of 89.7%, hence a mean fledgling per breeding attempt was 2.79. Our findings revealed relatively high hatching and fledgling rates for our study population, and bode well for the conservation of this small falcon in its poorly-known breeding range.
The Osprey Pandion haliaetus has recently been found in inland areas of Japan, but its diet there is not well understood. In this study, CCD cameras were used to monitor Osprey two nests in Iwate Prefecture during the 2017 breeding season. Both pairs (one nesting near a reservoir, one by a river) consumed introduced fish species, notably Largemouth Bass and Japanese crucian carp. Similar prey are also consumed by other Osprey populations in Japan, indicating that introduced fish may be among the major food resources of Ospreys throughout Japan.
The Tuxtla Quail-Dove Zentrygon carrikeri is a poorly known, micro-endemic, and endangered species of southern Mexico. Almost no information has been published about this dove. We provide new information about its natural history, which resulted from community-based bird monitoring programs. We describe unknown breeding, feeding, bathing, social, alert, and roosting behaviors of the species. Moreover, we highlight the relevance of participatory science for studying and engaging society in the conservation of the Tuxtla Quail-Dove. Our observations on the species provide valuable information for guiding future research and enhancing conservation activities on this species.
The Red-crowned Crane Grus japonensis is an endangered species in East Asia. The western flyway population in China has been in steady decline in recent years because of the loss and deterioration of the natural wetland habitat it requires. To enhance this migratory Red-crowned Crane population, a project was designed to return captive Red-crowned Cranes to the wild in 2013 and 2015 in the Yancheng National Nature Reserve (YNNR). This reserve is the most important wintering site for the continental migratory population. The survival rate of introduced Red-crowned Cranes was 40%. However, aggregation of introduced and wild individuals was not observed. Introduced individuals did not pair with wild individuals nor did they migrate to breeding areas with them. They remained in the core zone of the YNNR over summer. Here, we report the first breeding of introduced Red-crowned Cranes in the YNNR in 2017 and 2018. Suitable rearing methods and the use of aircraft to inform them of the migration route are necessary. Further research is necessary to confirm the migratory status of the cranes that are reared in the reserve.
Consumption of the berries of Morrow's Honeysuckle Lonicera morrowii has caused reddening of bird plumages in North America. We looked for examples of reddened feathers in Japanese birds, where the honeysuckle is native. We report the observation of legitimate reddened feathers in three Gray-headed Woodpeckers Picus canus, but are unsure whether the honeysuckle caused the color change in this instance. Morrow's Honeysuckle is uncommon in Japan, and birds rarely eat its berries. The availability of a wide variety of edible fruits may generally reduce the likelihood of avian plumage coloration being altered by shrubs such as the honeysuckle in Japan.
An important property of a foraging group is its density, particularly measured as nearest-neighbor distance. This study examined whether distance to the nearest neighbor changes over short time intervals in two fast-moving foragers, Dunlin Calidris alpina and Semipalmated Sandpiper C. pusilla, while at a spring stopover site in Delaware Bay, USA. For 181 focal individuals, nearest-neighbor distance was recorded in 5-s intervals for 60 seconds. For each focal individual, measured values were compared with those recorded at the beginning and end of observations, with the mean of values recorded at the beginning and end of observations, and with the mean of values recorded at the beginning, middle and end of observations. The results of this study indicate that single-point estimates of nearest-neighbor distance may not be appropriate in fast-moving foragers such as sandpipers.