Is nesting in closed nestboxes advantageous for the European Robin(Erithacus rubecula)?

Background:The European Robin(Erithacus rubecula)is eurytopic in its choice of nest site,which can be either half-open or closed,and situated either on the ground or at a height of several meters.On occasion,robins also nest in closed nestboxes,though generally only solitary such cases are documented,albeit that dozens of such events can be recorded during the course of some long-term studies.However,until now,nobody has summarised the peculiarities of robins nesting in closed nestboxes.Methods:In the period 1978-2020,wooden tit and starling nestboxes were inspected regularly at five study sites in Lithuania,this totaling more than 18,000 nestbox-seasons.During these inspections,90 cases of robins nesting in the nestboxes were recorded.Publications on this topic from the entire robin distribution range were reviewed.Results:Robins prefer to nest in old large-sized fairly shallow nestboxes with wide entrance holes,for example starling nestboxes or tit nestboxes with enlarged entrance holes.Increased numbers of nestboxes being occupied by robins were recorded for 3-8 years in row.In Lithuania,nesting success in nestboxes is not higher than compared with nesting on the ground.Tree climbing mammals,Pine Martens(Martes martes),Hazel Dormice(Muscardinus avellanarius),Edible Dormice(Glis glis)and Forest Dormice(Dryomys nitedula),are the main predators of robin nests in nestboxes.Conclusions:Some geographic variation was found in the occurrence of robins nesting in nestboxes with more such cases recorded in central and southern parts of the range.Possibly robins are more philopatric in these parts of the range,with the same females or their offspring nesting in nestboxes for several years in row.In areas inhabited by dormice,nesting in closed nestboxes is not advantageous for robins.

Nest predators, nest-site selection and nest success of the Emei Shan Liocichla(Liocichla omeiensis), a vulnerable babbler endemic to southwestern China

Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success.Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(DSR). Nest success was calculated using the Mayfield method.Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest success.Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.

Breeding biology of a relictual Maghreb Magpie(Pica mauritanica)population in Tunisia

Background:The Maghreb Magpie(Pica mauritanica)is an endemic North African species.Available knowledge on this species is limited to historic descriptive data with no ecological information provided.Populations continue to dramatically decline in Tunisia,where only one relic population survives.Investigating the breeding biology of this species is essential for conservation purposes.The purpose of this study was to increase our understanding of the Tunisian relic population and provide detailed data on breeding biology over two breeding seasons(2017 and 2018).Methods:This study occurred on a private farm of 650 ha,located 10 km from Dhorbania village at Kairouan Governorate,in central Tunisia.Active nests were monitored weekly during egg laying period and twice a week during hatching period.The Ivlev's electivity index was used to assess whether the frequency of use of nesting trees and bushes matched their availability in the study area.We recorded nest measurements and positions,and compared them using Wilcoxon signed-rank test.Variations of breeding parameters as number of eggs laid,hatchlings,and fledglings over years were performed using Mann–Whitney U-test andχ^(2) tests.We used a Generalized Linear Mixed Model(GLMM)to investigate how egg volume varied with clutch size and laying date.Results:We investigated clutch size,egg size,hatching and fledging success,and evaluated how these parameters varied according to laying date and nest characteristics.Clutch size averaged 5.00±0.19 but was significantly greater nest.Causes of nest failure included the depredation of nestlings by shrikes,cobras and rats(e.g.Lanius meridionalis,Naja haje and Rattus rattus),death of parents by the Black-shouldered Kite(Elanus caeruleus)and nest parasitism by the Great Spotted Cuckoo(Clamator glandarius).Clutch size,brood size and fledgling success were unaffected by laying date,nest volume and nest elevation.Egg volume decreased with laying date but was unaffected by clutch.Conclusion:Our study provides the first and only detailed data on reproductive parameters of the Maghreb Magpie in its entire geographic range(North Africa).Information gleaned from this study provides valuable information for monitoring and long-term conservation plans of the endangered Tunisian Magpie population.Additionally,our data provide an avenue of large-scale comparative studies of the reproductive ecology of the magpie complex.