Repeated use of high risk nesting areas in the European whip snake, Hierophis viridiflavus

Oviparous snakes deposit their egg clutches in sites sheltered from predation and from strong thermal and hydric fluctuations. Appropriate laying sites with optimum thermal and hydric conditions are generally scarce and are not necessarily localised in the home range. Thus, many gravid females undertake extensive trips for oviposition, and many may converge at the best egg laying sites. Dispersal mortality of neonates post-hatchling is also a critical factor. Assessing the parameters involved in this intergenerational trade-off is difficult however, and no study has succeeded in embracing all of them. Here we report data indicating that gravid females of the highly mobile European whip snake, Hierophis viridiflavus exhibit nest site fidelity whereby they repeatedly deposit their eggs in cavities under sealed roads over many decades. These anthropogenic structures provide benefits of relative safety and suitable incubation conditions (due to the protective asphalted layer?), but they expose both females and neonates to high risk of road mortality. Artificial laying sites constructed at appropriate distances from busy roads, along with artificial continuous well protected pathways (e.g. dense hedges) that connect risky laying sites to safer areas, should be constructed.

Nest-site fidelity and breeding dispersal by Common Tailorbirds in a tropical forest

Background Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation. Methods By using mist nets and tracking the color banded individuals, we investigated nest-site fidelity and breeding dispersal by Common Tailorbirds (Orthotomus sutorius) throughout a year and between successive years in 2017–2018. Results The present study showed that Common Tailorbirds could produce up to four clutches per breeding season. When multiple broods were produced within a year, breeding pairs remained together, and the nest rebuilding rate was up to 92.2%, with only four cases (7.8%) in which birds reused their old nests. The dispersal distance between the nests during multiple breeding was found to be 10.0 ± 10.5 m, and nest-site fidelity within the same year was 90.0%. By the second year of breeding, 76.2% of individuals remained in the original breeding pairs, while for those that did switch partners, the females remained in the nest from the previous year and paired with new males. The dispersal distance between years was 26.5 ± 41.9 m, and nest-site fidelity between different years was 80.1%. There was no significant difference between within-year and between-year dispersal distances. Moreover, there was no significant difference in the dispersal distance of rebuilt nests between birds that had experienced nest predation and those that had not. Conclusions Our findings suggest that Common Tailorbirds maintain a high degree of fidelity to mates and nest-sites, and nest predation had no significant effect on territorial changes or breeding dispersal distance between each breeding attempt.

Nest-site fidelity in Lesser Kestrels: a case of Win–Stay/Lose–Shift?

We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that depends on the outcome of the previous nesting attempt in that site. In particular, we were interested in examining whether individual kestrels practice a Win–Stay/Lose–Shift (WSLS) strategy towards their nest-sites; that is, does the tendency to use the same nest-site increase following a successful nesting season, but decrease following a failure. For that purpose, we documented the use of nest-sites by Lesser Kestrels and the breeding success in these sites during 1998–2003 in the city of Jerusalem (Israel). We found that while Lesser Kestrels do not practice WSLS strategy towards their nest-site, the males (but not the females) do so towards their sub-colony – they tend to stay in the same sub-colony if their nesting was successful, whereas they tend to migrate to a different sub-colony after failure. A possible explanation to this sexual difference in WSLS behavior can arise from the fact that changing a sub-colony entails a change of hunting area. The male, being the main food provider in the Lesser Kestrel, may be more sensitive to this opportunity.

Breeding behaviour and productivity of Black-necked crane (Grus nigricolis) in Ladakh, Indian Trans-Himalaya

A long-term study was conducted to understand some aspects of breeding biology of Black-necked crane (Grus nigricollis) in Changthang, Ladakh. Data on aspects such as the breeding season, courtship, mating, egg laying and incubation period, nest site fidelity, egg morphometry, breeding productivity and recruitment rate were collected between 2003 and 2012. Black-necked crane started arriving from last week of March to first half of April and showed fidelity at ten nesting sites. Courtship and mating peaked early morning (0700 hours), around noon (1100 hours) and in late evening (0600 hours) while the nest building at evening (1600 hours). The egg laying period initiated in May and extended up to July. The average incubation period was 33.88±0.3 days. Hatching success, nest survival rate and fledgling increment rate of the bird were 73.3%, 0.55 ± 0.03 and 0.41 ± 0.02 respectively with an overall breeding productivity of 0.73. The present population of Black-necked crane in Changthang, Ladakh seems to stable with an average recruitment rate of 15.7±1.4.