Breeding Attempts Research Articles

Population trends and diversification of breeding habitats of Peregrine Falcon (Falco peregrinus) in the Czech Republic since 1990

Abstract The population of the Peregrine Falcon (Falco peregrinus) in the Czech Republic recovered from a nearly total extinction during the 1960s and 1980s (0­3 breeding pairs) and the first successful breeding after this interval was confirmed in 1995. The increase of the population size accelerated after 2000 and it is still growing despite the limited amount of suitable natural breeding opportunities. There were 89 known pairs in 2016, 70 of them were proven to breed with altogether at least 121 reared young. Several breeding attempts on historical buildings in city­centres were recorded up to 2002 (in Prague and Pilsen), but this breeding habitat was abandoned later. More and more pairs are nowadays breeding on industrial buildings. The first breeding on a power plant chimney, 300m above the ground was discovered in 2010. Moreover, 16 breeding pairs were found on industrial buildings in 2016 (mainly tall chimneys or cooling towers and power­plant buildings), all of them breeding in nest boxes. The colonization of industrial buildings started in western part of the Czech Republic and continues eastwards every year. Currently, the easternmost colonized building is in Mladá Boleslav. We have no recent tree­breeding pairs and all eight published historical cases are at least doubtful. Most of the observed Peregrines ringed abroad came from Germany, indicating a strong influence of German population on restoration of the population in the Czech Republic. Within these recoveries, some of Peregrines were released in the tree­breeding population restoration project in Germany and Poland, but all these birds bred on rocks.

Long-term monitoring of a successful recovery program of Peregrine Falcons in Virginia

Abstract The Peregrine Falcon (Falco peregrinus anatum) was believed to be extirpated as a breeding species in Virginia by the early 1960s. An aggressive restoration program was initiated in 1978 that involved the release of captive-reared birds totaling 115 on the Coastal Plain (1978–1985) and 127 in the Mountain physiographic region (1985–1993). The first occupied territory was established and the first breeding attempt was documented in 1979 and 1982, respectively. We have monitored the size, distribution, reproductive rate, and substrate use of the resulting breeding population (1979–2016). The population proceeded through an establishment phase (1979–1993) driven by releases with an average doubling time of 3.8 yrs to a consolidation phase (1994–2016) with an average doubling time of 23.1 yrs. The state supported 31 breeding pairs by 2016. Per capita reproductive rates have increased significantly over the study period from 0.89 (1979–1993) to 1.86 (1994–2016). Average nesting success increased from 67.1% to 82.7% over the same period. Nesting attempts (n = 469) have been documented on dedicated peregrine towers (52.1%), bridges (26.1%), buildings (4.1%), and various man-made structures (13.0%) with only 4.7% documented on natural cliffs. The population appears to be self-sustaining with reproductive rates exceeding 1.5 young/pair every year since 1999. An ongoing management concern is that only 8.9% of known territories (n = 45) identified since introductions and 4.7% of documented breeding attempts (n = 469) have occurred within the historic mountain breeding range.

Results of eighteen years (2000–2017) monitoring study of an extra-alpine Peregrine Falcon Falco peregrinus population in North-Western Italy

Abstract The Author reports the results of a survey about a breeding extra-alpine Peregrine Falcon population in Cuneo Province, NW Italy. The first reproduction was recorded in 2000, and from that year, the monitoring work localized 16 occupied territories in an area of 1,900 km2 covering the hills and nearby lowland areas. The average distance between breeding territories was of 7.6 km with a density 0.7 pairs/100 km2. During the eighteen years, 89 successful breeding attempts were recorded, 81 of them led to fledging of 206 young. Average breeding success was 2.5 juv/reproducing pairs. The nests are located on bridges (motorway viaducts and rail way bridges) and clay/sandstone cliffs. Preliminary prey analyses showed that pigeons and doves represent the 75% of their diet.

Male Assistance in Parental Care Does Not Buffer Against Detrimental Effects of Maternal Inbreeding on Offspring

The severity of inbreeding depression often varies across environments and recent work suggests that social interactions can aggravate or reduce inbreeding depression. For example, stressful interactions such as competition can exacerbate inbreeding depression, whereas benign interactions such as parental care can buffer against inbreeding depression in offspring. Here, we test whether male assistance in parental care can buffer against the detrimental effects of maternal inbreeding on offspring fitness in the burying beetle Nicrophorus vespilloides. Our results confirm that maternal inbreeding had detrimental effects on offspring survival. However, we found no evidence that male assistance in parental care buffered against those effects on offspring fitness. Outbred females benefitted from male assistance, gaining more weight over the breeding attempt when assisted by a male. In contrast, inbred females did not benefit from male assistance, gaining as much weight regardless of whether they were assisted by a male or not. Surprisingly, we find that males gained more weight during the breeding attempt when mated to an inbred female, suggesting that males benefitted from assisting an inbred female partner in terms of their weight gain. Overall, our findings suggest that parental care or other benign social interactions may not always buffer against detrimental effects of inbreeding depression.

The structure and context of male and female song in White-throated Dippers

Female song in birds is more widespread than previously thought but remains poorly studied. Relatively few researchers have compared the structure and function of female song with that of conspecific males, especially in non-duetting species. Here we investigate male and female song in the White-throated Dipper (Cinclus cinclus; hereafter ‘Dipper’), a highly territorial and largely monogamous passerine with a complex song in both sexes. The songs of individually marked birds were recorded over a 3-year period in order to compare the acoustic structure and production of song in males and females at different stages of the breeding cycle. No differences were found in the complexity, frequency or temporal characteristics of male and female songs. However, unpaired males recorded early in the breeding season sang more complex songs than males that were paired up and nest-building or whose breeding attempts were underway, suggesting that male song is used for mate attraction. By contrast, females sang most often during aggressive encounters with birds from outside their territory. Furthermore, males sang throughout the breeding season, when they are highly territorial, whereas females rarely sang after laying had begun. Together, these results support findings from other species that song structure varies with context and suggest that female song in Dippers may be used primarily in mate or territory defence.

Are farming and birds irreconcilable? A 21-year study of bustard nesting ecology in intensive agroecosystems

Farmland landscapes in developed countries have undergone major habitat changes over the past 60 years leading to the decline of many species. Of these, the little bustard, a medium-sized, long-lived, ground nesting bird, has declined by 95% in France over the last 35 years. Here we present the results of a 21 year survey of the nesting ecology of this elusive species, analyzing 157 breeding attempts, the largest data set ever collated for this species. Females had a strong preference for meadows for breeding, yet this habitat only represented 14% overall habitat. Alfalfa alone accounted for 50% of nest locations. However, apart from vegetation type, females did not show any other pattern of habitat selection (vegetation height, nest position within field, field under agri-environmental contract-AES-). In addition, the laying period was extremely extended, spanning almost 3 months. We did not detect any strong effect of crop, date or whether the nesting field was in AES or not, on clutch size, egg size and egg-laying date. However, there were long-term changes in breeding phenology (females breed earlier than 20 years ago), and selection of vegetation between years and within years. Hatching success was very low (about half of the broods were destroyed by farm work), and both fecundity and productivity per female were found to be approximately one third of the values expected for a stable population. Overall, nesting females of Little Bustards select meadows in regard to their availability, but do not show any particular preference within meadows' vegetation structure or height. We show that in such system, meadows act as ecological traps, and furthermore, because females do not appear selective, it is impossible to manage meadows in order to limit this trap. We finally analyze whether the land-sharing AESs can conserve this species in intensive arable systems and conclude that the land sharing may not be sustainable. We discuss our results in light of the alternative of land sparing, and suggest that this is probably a better fit for the conservation of large-bodied bird species given their ecological constraints (large home ranges, presence of semi-natural landscape components and freedom from human interference).

Häckningsframgång hos ormvråk Buteo buteo och kattuggla Strix aluco i Varbergs kommun 1984–2016

In 1984–2016 we studied the habitat choice, nest placement and breeding success of Common Buzzard Buteo buteo and Tawny Owl Strix aluco in the municipality of Varberg in southwest Sweden (57°10'N, 12°10'E). The analyses are based on 1,512 successful breeding attempts of Common Buzzard, and 1,387 of Tawny Owl. The average number of young per successful breeding was 1.74 and 2.86, respectively. The variation between years was highly correlated between the two species, suggesting a common food source. In both species the between-year variation in clutch size was particularly large in beech forest territories, most likely caused by the effect of beech mast years on local rodent populations. The breeding density of Common Buzzard was particularly high in 1990–1995, coinciding with large areas of farmland set-aside. In the Common Buzzard, the yearly average number of young per clutch declined significantly with yearly average hatching date.

Risk assessment analysis of potato genotype susceptibility to water rot-causing oomycetes

Water rots are a group of important potato tuber rot diseases such as pink rot, Phytophthora tuber rot, and leak caused by the oomycete pathogens Phytophthora erythroseptica, P. nicotianae, and Pythium ultimum, respectively. If not managed, these diseases either alone or in combination, can cause severe yield loss and substantial reductions in quality. Growers continue to rely on fungicides for water rot management in the field and during post-harvest storage. Previous and ongoing breeding attempts have failed to identify and develop commercially acceptable potato cultivars resistant to all three diseases. This is mainly due to the complex, expensive, and time-consuming methodologies required to screen for susceptibility to water rot pathogens. Currently, potato genotypes are assessed for susceptibility to individual water rot pathogens which is labor intensive. Considerable savings in time and effort would be realized if potato genotypes could be evaluated for susceptibility to one water rot pathogen and then statistical analysis applied to determine the probability of the reaction of a genotype to the other rot pathogens. A proportional odds model was fitted to examine the risk of genotype screening outcome (ordinal) to understand the relationships among water rot causing oomycetes in potato. Compared to P. erythroseptica, P. ultimum infected genotypes having susceptibility risk was high (2.6) versus other cultivar susceptibility categories. Potato genotypes screened for P. nicotianae have a significant susceptibility risk decreased by 38% when compared to P. erythroseptica.

Socially regulated estrogen in an eavesdropping brood parasite

Social regulation of reproductive hormones is a means by which conspecific males and females orchestrate successful reproductive efforts. We investigate whether social cues modify activity within the hypothalamic-pituitary-gonadal (HPG) axis and the specificity of this response in a social parasite that is known to eavesdrop on the communication signals of other species: the brown-headed cowbird (Molothrus ater). Brown-headed cowbirds are obligate brood parasites that do not build nests or care for their own young. Instead, obligate brood parasites leave their eggs in the nest of a host species and therefore must coordinate their breeding attempts with conspecifics as well as potential heterospecific hosts. Here, we explore whether the vocal signals of potential host species can also be used as a social cue that modifies the HPG axis of female brown-headed cowbirds. Results reveal that both conspecific and heterospecific song-exposed females exhibit significantly greater circulating estradiol concentrations as compared to silence-exposed females. While conspecific song induces the greatest elevation in circulating estradiol, there is no significant difference in circulating estradiol levels in females exposed to either conspecific or heterospecific songs. This pattern suggests both song types are effective at evoking a reproductive physiological response. On the other hand, circulating progesterone concentrations did not differ among the song- and silence-exposed groups nor did the size of the female’s ovarian follicles. These results indicate that heterospecific vocal communication signals can effectively be used as a social cue that simultaneously provides necessary information regarding breeding status of hosts and modifies breeding condition of the eavesdropper.

Time, geography and weather provide insights into the ecological strategy of a migrant species

Farmland and migratory bird populations are in decline. The Common quail (Coturnix coturnix) provides an exception to this trend and its populations have remained stable over the last two decades. However, some basic facts regarding quail biology and ecology, such as the geographic distribution of age and sex classes during the summer, remain poorly understood. We analyzed 43,194 Spanish quail ringing records from 1961 to 2014 to assess the effects of geography and weather conditions on the probability that individuals will be ringed during the various stages of their annual cycle (arrival –spring migration-, stationary breeding period, departure –autumn migration- and winter) for the different quail age-sex classes over time. We found that spatial distribution of the age and sex classes can be explained by date, latitude, longitude, altitude, rainfall, and temperature. Our results suggest that date accounts for most of the variation in the distribution of quail age classes, followed by the weather variables, and then latitude, and altitude. Similarly, date also accounts for most of the variation in the distribution of the two sexes. These results could partially explain why this species has avoided population decline, since its ecological strategy is based on its temporal and spatial distribution combined with the segregation of age and sex groups. We hypothesize that the distribution of quail age and sex classes follows variations in weather and habitat suitability to exploit seasonal and geographic variations in resource availability. The migratory and nomadic movements of quail, combined with the occurrence of multiple breeding attempts within a single season, may also allow these birds to overcome the impacts of predators and anthropogenic environmental change. Conservation and management efforts should therefore take account of these age and sex related temporal and spatial patterns.

A major QTL on chromosome C05 significantly reduces acid detergent lignin (ADL) content and increases seed oil and protein content in oilseed rape (Brassica napus L.).

A reduction in acid detergent lignin content in oilseed rape resulted in an increase in seed oil and protein content. Worldwide increasing demand for vegetable oil and protein requires continuous breeding efforts to enhance the yield of oil and protein crop species. The oil-extracted meal of oilseed rape is currently mainly used for feeding livestock, but efforts are undertaken to use the oilseed rape protein in food production. One limiting factor is the high lignin content of black-seeded oilseed rape that negatively affects digestibility and sensory quality of food products compared to soybean. Breeding attempts to develop yellow seeded oilseed rape with reduced lignin content have not yet resulted in competitive cultivars. The objective of this work was to investigate the inheritance of seed quality in a DH population derived from the cross of the high oil lines SGDH14 and cv. Express. The DH population of 139 lines was tested in field experiments in 14 environments in north-west Europe. Seeds harvested from open pollinated plants were used for extensive seed quality analysis. A molecular marker map based on the Illumina Infinium 60K Brassica SNP chip was used to map QTL. Amongst others, one major QTL for acid detergent lignin content, explaining 81% of the phenotypic variance, was identified on chromosome C05. Lines with reduced lignin content nevertheless did not show a yellowish appearance, but showed a reduced seed hull content. The position of the QTL co-located with QTL for oil and protein content of the defatted meal with opposite additive effects, suggesting that the reduction in lignin content resulted in an increase in oil and protein content.

Isolating the roles of movement and reproduction on effective connectivity alters conservation priorities for an endangered bird

Movement is important for ecological and evolutionary theory as well as connectivity conservation, which is increasingly critical for species responding to environmental change. Key ecological and evolutionary outcomes of movement, such as population growth and gene flow, require effective dispersal: movement that is followed by successful reproduction. However, the relative roles of movement and postmovement reproduction for effective dispersal and connectivity remain unclear. Here we isolate the contributions of movement and immigrant reproduction to effective dispersal and connectivity across the entire breeding range of an endangered raptor, the snail kite (Rostrhamus sociabilis plumbeus). To do so, we unite mark-resight data on movement and reproduction across 9 years and 27 breeding patches with an integrated model that decomposes effective dispersal into its hierarchical levels of movement, postmovement breeding attempt, and postmovement reproductive success. We found that immigrant reproduction limits effective dispersal more than movement for this endangered species, demonstrating that even highly mobile species may have limited effective connectivity due to reduced immigrant reproduction. We found different environmental limitations for the reproductive component of effective dispersal compared with movement, indicating that different conservation strategies may be needed when promoting effective dispersal rather than movement alone. We also demonstrate that considering immigrant reproduction, rather than movement alone, alters which patches are the most essential for connectivity, thereby changing conservation priorities. These results challenge the assumption that understanding movement alone is sufficient to infer connectivity and highlight that connectivity conservation may require not only fostering movement but also successful reproduction of immigrants.

Overexpression of a maize (Zea mays) defensin-like gene in maize callus enhances resistance to both insects and fungi

Identification of genes responsible for pest resistance in maize will assist with breeding attempts to reduce crop losses and hazards due to toxins produced by mold infecting ears. A gene coding for a defensin-like gene was cloned from an inbred reported to be resistant to Fusarium proliferatum and Fusarium verticillioides ear rot, based on its location in a QTL associated with resistance to those and other species of ear rot molds that produce mycotoxins. The gene was expressed transgenically in maize callus and the construct presence confirmed in transformants by PCR analysis and by detection with antibody made to a portion of the protein. Positive transformants were more resistant to corn earworms (Helicoverpa zea) and fall armyworms (Spodoptera fruigperda) as indicated by significantly lower weights compared to control callus expressing a β–glucuronidase (GUS) gene. Positive transformants also had significantly less visible growth of F. proliferatum and F. verticillioides, but not Fusarium graminearum, than controls. This indicates for the first time a defensin that is active against both insects and fungi, thereby allowing for more effective breeding for resistance to both major classes of pests attacking maize.

Nesting behaviour and breeding success of Willow Tits Poecile montanus in north-west England

ABSTRACTThe British Willow Tit Poecile montanus has undergone a substantial decline in abundance and a severe contraction in range since the 1970s, for reasons that are poorly understood. Breeding failure, due to nest-site competition and predation, has been suggested as a potential factor in the decline, but limited data exist for the nesting ecology and breeding productivity of the species in Britain. We studied a sample of 128 Willow Tit nests in a habitat mosaic of early successional woodland, scrub and wetland in a post-industrial landscape in north-west England, which is increasingly becoming a key refuge for the species in Britain. Results showed that nesting began in April, with standing deadwood of silver birch Betula pendula, common elder Sambucus nigra and black alder Alnus glutinosa being the most frequent nest sites, and the characteristics of nest sites are described. Daily survival rates and overall probability of nest survival are calculated, and details are given for the timing of breeding, clutch size, nestling survival and number of fledglings produced. Overall, 55% of nesting attempts were successful, although many first breeding attempts failed due to Willow Tits being evicted from their nest cavity by Blue Tits Cyanistes caeruleus, or nests being predated by Great Spotted Woodpeckers Dendrocopos major and, potentially, grey squirrels Sciurus carolinensis. Repeat breeding attempts were relatively more successful, but produced fewer fledglings on average. The results are discussed in the context of other studies of Willow Tits and some related species, and also the implications for the conservation of Willow Tits in Britain.

Artificial nests for Barn Swallows Hirundo rustica: a conservation option for a declining passerine?

ABSTRACTCapsule: Barn swallows Hirundo rustica using artificial nest cups had greater reproductive success than those building and using natural nests.Aims: To quantify reproductive success of Barn Swallows breeding in artificial man-made nests and compare with those using natural nests.Methods: In 2012–16, the breeding attempts of 231 pairs of Barn Swallows were monitored in artificial and natural nests in an urban habitat in Denmark.Results: Pairs breeding in old natural nests and artificial nests bred earlier, laid more eggs, and produced more nestlings and fledglings than pairs breeding in new natural nests. Inter-clutch intervals were shorter in Barn Swallow pairs using artificial nests and old natural nests. Nest cup volume and nest volume of newly built nests were significantly larger and more variable than artificial nests excluding an effect of nest size as an explanation for the larger clutches laid in artificial nests. Increased energy and time costs of nest construction may have reduced reproductive success for pairs building natural nests.Conclusion: Artificial nests were readily accepted by Barn Swallows, they had a similar low predation rate as natural nests, and they proved to be a possible conservation option for this declining passerine breeding in urban habitats as evidenced by their 75% higher reproductive success in artificial nests.

Overlapping breeding attempts in the Bearded Tit (Panurus biarmicus)

BackgroundOverlapping of successive broods is a relatively rare breeding strategy that allows individuals to make effective use of the available reproductive window.MethodsIn this paper we analyse the occurrence of overlapping breeding attempts in the Bearded Tit (Panurus biarmicus), a non-migratory passerine species, whose peripheral populations vary enormously in numbers.ResultsThe colour-ringed population of Bearded Tits was studied in western Poland in 1990, 2012–2013 and 2015–2017. Overlapping broods were found only during years with low population sizes and low densities (1.2–3.6 pairs per 10 ha), and pairs with such broods constituted 11.1–20%. In years with higher population densities (8.7–13.44 pairs per 10 ha) overlapping broods were not recorded. Pairs started building the next (overlapping) nests when their young were 3–10 days old. They divided their duties while rearing two broods simultaneously: females were occupied only with the new clutch, while males, in contrast to other species with brood overlap, not only fed the young from an earlier brood, but also helped the females with the building of a new nest and incubation of a new clutch.ConclusionsLaying overlapping clutches enabled pairs to shorten their average breeding cycle by 15–21 days and produce more offspring. It is possible that overlapping breeding attempts is a density-dependant strategy, enabling the population to restore after severe declines, however, alternative explanations are also possible. Future studies are needed to better understand mechanisms underlying the occurrence of this phenomenon.

Population age structure as an indicator for assessing the quality of breeding areas of Common quail (Coturnix coturnix)

Quality breeding areas are vital for the management and conservation of migratory bird species, especially those under pressure from climate warming effects. The Common quail Coturnix coturnix is a migratory species characterized by its itinerant breeding (several breeding attempts in different places) and exposure to high mortality rates, and it is a case in point. The identification and management of high quality nesting areas is essential to conserve this and other migratory species. Here, we use a Spanish long-term quail ringing dataset (1961–2014) to correlate population age structure with temporal and geographical variables. We show that northern Mediterranean regions provide optimal breeding sites and have balanced population age structures (young:adult males). The proportion of young:adult males provides an indicator of the relative quality of various breeding areas. Records of ringed quail provide data on the overlap between young and adult males temporarily resident in different geographic areas and may provide a useful tool to evaluate habitat quality. We found that the timing of sequential breeding attempts and temporary residency of quail are associated with latitude, altitude, and geographic location of quail ringing records. In southern regions, young males arrive at the breeding area later than adults, while in northern regions young birds and adults arrive at same time. Optimal breeding areas are characterized by high quality habitat, have high quail densities, and a mixture of young and adult males, factors that favour sexual selection, heterozygosity and population viability. However, not all high quality habitat areas are suitable for reproduction, being necessary enough quail density and the adequate proportion of young:adult males.

The effect of gentamicin/kanamycin treatment on in vitro contamination of rabbit spermatozoa with selected bacterial strains

Breeding attempts to increase the oil in the seed and to reduce the fibre content in the meal have led to the development of yellow-seeded B. napus canola and canola-quality B. juncea. The objective of the current study was to evaluate the chemical and nutritive composition of meals derived from yellow-seeded B. napus and B. juncea canola in comparison with the meal from conventional black-seeded B. napus canola. Apparent metabolisable energy (AMEn) and standardised ileal amino acid digestibility (SIAAD) of the three canola meals (CM) were determined with broiler chickens of 14 to 19 d of age (AMEn assay), or 14 to 21 d of age (SIAAD assay) using 6 cages of 6 birds each per treatment. The nutritive value of CM was further validated in a 35-day performance study using 7 cages of 50 broiler chickens per treatment, including a control group without CM. Birds were fed wheat/maize/soybean meal-based diets containing 150 g/kg of canola meals in the starter (1–10 d), grower (11–24 d), and finisher (25–36 d) phases of the experiment. In comparison with the conventional meal, these from yellow-seeded B. napus and B. juncea contained, on dry matter (DM) basis, more crude protein (434 and 472 vs. 411 g/kg), more sucrose (101 and 80 vs. 66 g/kg), and less total dietary fibre (298 and 289 vs. 350 g/kg), respectively. The highest content of all essential amino acids (except cysteine) was observed in B. juncea meal. The AMEn and mean SIAAD coefficients for yellow-seeded B. napus, B. juncea canola, and the conventional black-seeded B. napus were 7.80, 8.75 and 7.96 MJ/kg DM, and 0.83, 0.83, and 0.82, respectively. In the growth performance study, body weight gain (BWG) was significantly lower for the yellow-seed B. napus meal as compared with the Control and the black-seed B. napus and B. juncea meals (2.19, 2.32, 2.30, and 2.31 kg/bird, respectively). No significant difference in feed conversion ratio (FCR) between the Control and diets containing the three CM were observed indicating that all types of CM could be used effectively and replace soybean meal (SBM) in broiler chicken rations, providing that the diets are formulated based on digestible amino acids and available energy contents.

Breeding Biology of the Mottled Wood-Owl (Strix ocellata) in West-central India

The Mottled Wood-Owl (Strix ocellata) is a poorly studied species endemic to the Indian subcontinent. During nine nesting seasons from 2005–2016, we studied 15 breeding pairs near Pune, west-central India. Important nest tree species were mango (Mangifera indica, 52%) and tamarind (Tamarindus indica, 22%). Habitat in plots with a 0.5-km radius centered on the nest comprised a mosaic of agricultural landscapes (41.9 ± 17.7%), deciduous/scrub forests (16.8 ± 21.8%), natural grasslands (15.0 ± 8.2%), human habitation (11.2 ± 8.5%), streams/rivers (10.1 ± 4.6%), and low hills (5.0 ± 5.8%). In a subset of five nests where the entire breeding cycle was studied, the average clutch size was 2.6 eggs (±0.5 SD, n = 20 breeding attempts [eggs laid]), of which an average 2.2 (± 0.4) young hatched, and 1.9 (±0.8) young fledged/ breeding attempt. In addition, among ten other pairs where the nests were detected at the stage of fledging of young, an average of 1.6 young (±0.7, range = 1–4) fledged / successful nest. The primary nesting season from egg-laying to fledging lasted from 10 February until 20 May. From 1033 pellets analyzed, we identified 711 prey, including insects (39%), small mammals (rodents 10%; shrews 21%, bats 3%), birds (11%), and reptiles (9%).

The individual courtship behaviour of male European mink (Mustela lutreola) is a good indicator for their breeding success

Conservation breeding of the critically endangered European mink (Mustela lutreola) is a challenge, because the genetically prioritised breeding pairs often fail to mate during the staged breeding attempts. For this study the courtship and mating behaviour of 33 males and the response behaviour of 28 females was observed and recorded throughout two breeding seasons at Tallinn Zoo using an ethogram. The behavioural patterns of the male European mink differed significantly depending upon their previous reproductive success and the outcome of the breeding attempt. “Clucking”, “flehmen”, “chase”, “anal drag”, “neck bite” and “mounting” were observed significantly more often among males that sired a litter during the study (“breeding males”) and during attempts that ended with copulation. More than half (61%) of the males were “non-breeding males”: they never sired a litter or copulated with a female. Females “chirped” significantly less often in attempts with “non-breeding males”. The male “clucking” sound was the best indicator to predict 1) a males ability to sire a litter and 2) whether a breeding attempt would end with copulation. The absence of species-specific courtship and mating behaviour in the “non-breeding males” threatens the conservation goal to maintain the genetic heterozygosity of the captive population. From a practical point of view, behavioural indicators could be used as a potential screening method for identifying successful future breeders. In an experimental setup, males were presented with scent cues from an oestrous female but without the opportunity for direct contact. In this experimental context 64% of “breeding males” responded with “clucking” and also presented “flehmen”, “rubbing” and “approach to the female/her nest box door” significantly more often than the “non-breeding males”.