Roosting patterns of House Sparrow Passer domesticus Linn., 1758 (Aves: Passeridae) in Bhavnagar, Gujarat, India

The House Sparrow Passer domesticus is widely distributed across the world, and local alarming declines in sparrow populations have prompted studies focused on this species. An understanding of fundamental life history aspects such as roosting patterns is necessary for the development of efficient conservation strategies. This study examined House Sparrow roosting patterns in urban, suburban and rural areas of Bhavnagar during 2017–2018. Potential roosting sites were identified, and peak arrival/ departure times and roosting duration of sparrows were recorded. We found that peak arrival and departure times were correlated with solar timings, indicating a strong influence of photoperiod on sparrow behaviour. Little variation was observed in sparrow arrival and departure times across the urban, suburban and rural gradient. However, arrival duration was significantly larger in urban and suburban areas. This may be due to the restricted availability of suitable patches within these habitats, requiring birds to spend more time foraging. House Sparrows mostly preferred thick vegetation for pre-roosting activities and roosting, and the loss of thick vegetation poses a threat to sparrow populations worldwide. In addition to increasing nesting opportunities by providing artificial nest sites, the importance of retaining appropriate habitats should be a major focus of conservation strategies.

The Occupancy of Barn Owl in the Artificial Nest Box to Control Rice Field Rat in Yogyakarta Indonesia

One component of integrated rat management in rice fields is barn owl as biological control. The study was conducted to evaluate the occupancy rate of barn owl nest boxes, the local rat population, and rat damage to rice crops. It was conducted in three locations in Yogyakarta by observing 10 nest boxes per site. Assessment of their occupancy was monitored by barn owl presence in nest box (egg, chick, and adult) and natural nests in villages nearby. In comparison with control village, the local rat population was observed by the active burrow count method and linear trap barrier systems. Rat damage intensity is estimated by sampling 150 tillers using a stratified sampling approach. The result indicated that 1-4 nest boxes were occupied per location. The owls also nested within buildings nearby. Active burrows ranged from 4 to 25 burrows per 150 m. The rat damage area ranged from 33.33% - 48.57% with 6.33% - 14.86% damage intensity was significantly lower than the control site. Artificial nest box installation for owls in rice fields were only occupied for breeding. The use of barn owls for biological control of rice field rats should be combined with other methods in an integrated approach.

Ecological and Genetic Monitoring of a Recently Established Osprey (Pandion haliaetus) Population in Wales

ABSTRACT The Osprey (Pandion haliaetus) experienced severe declines in Europe over the past centuries, including extirpations from large parts of its range. After Ospreys began naturally recolonizing Wales, United Kingdom (UK), in 2004, the Dyfi Osprey Project initiated an extensive ecological (ringing, satellite tracking, and nest video recordings) and genetic (microsatellite genotyping) monitoring program alongside artificial nest platform construction. From 2004 to 2019 there were 40 reproductive events (i.e., eggs laid in a nest) across six nests, resulting in a total of 95 fledglings and a yearly average of 2.35 ± 0.8 (SD) fledglings per nest-with-eggs. Video recording at one nest documented high hatching success and survival to the fledging and dispersal phases, as well as mate- and nest-fidelity across multiple years. Collectively these breeding parameters suggest high productivity associated with artificial nest structures and limited density-dependent effects for the Welsh population due to its small size and low density at this stage of recovery. Satellite tracking of four migrating individuals revealed that Ospreys used a western European migratory flyway and wintered in sub-Saharan western Africa. Genetic analysis of nestlings from five nests indicated single paternity in all cases, in agreement with evidence of social monogamy. Genetic analysis of geographical outgroups (Scottish, Swedish, and Latvian) provided preliminary evidence of cryptic population structure among UK (Welsh and Scottish) populations. The novel combination of loci show Welsh Osprey retain high levels of variation and more broadly direct reconsideration of the hitherto inferred genetic poverty of the species compared to other raptors. We recommend implementation of similar long-term ecological and genetic monitoring programs for other populations.

Nest Size Matters: Common Cuckoos Prefer to Parasitize Larger Nests of Oriental Reed Warblers

BackgroundAvian brood parasites leave parental care of their offspring to foster parents. Theory predicts that parasites should select for large host nests when they have sufficient available host nests at a given time. We developed an empirical experimental design to address this hypothesis by studying nest choice of common cuckoos (Cuculus canorus) among nests of its Oriental reed warbler (Acrocephalus orientalis) hosts.ResultsWe presented two groups of experimental nests: 1) nest dyads comprise one large and one small artificial nest from reed leaves, and 2) nest triads tied together use the modified old own warbler nests including enlarged, reduced and medium sized nests to elicit parasitism by common cuckoos. We predicted that cuckoos prefer larger nests over medium sized ones, and over the smallest nest. Our experimental findings show that common cuckoo females generally prefer large nests over medium or small sized nests. Furthermore, experiments showed that cuckoo parasitism was significantly more common than in previous studies of the same warbler population.ConclusionsOur results implying that larger, taller and more exposed host nests effectively increased the probability of cuckoo parasitism.