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Bird sex determination is fundamental in various ecological and biological studies, although many avian species cannot be sexed visually due to their monomorphic and/or monochromatic appearance. Thus, reliable laboratory methods for sexing are a prerequisite. Most avian nestlings lack sex-related signs, including the Eurasian pygmy owl (Glaucidium passerinum). We performed laboratory sex determination analysis of this species using blood samples of 242 juveniles and nine adults. It relied on the qPCR of the specific intron from the chromo-helicase DNA-binding protein 1 gene. We tested three primer sets, the P2/P8, 2550F/2718R, and CHD1F/CHD1R, commonly used for bird laboratory sexing. The outcomes were displayed on an agarose gel electrophoresis and a plot from melt curve analysis, which had not been previously conducted in Eurasian pygmy owls. We found that only primer set CHD1F/CHD1R proved reliable, as the only one determined sex with one and two band/s and peak/s on the electrophoresis and the melt curve plot for males and females, respectively. The other two primer pairs failed and depicted one band/peak in all specimens regardless of their sex. Therefore, we recommend performing Eurasian pygmy owls' laboratory sexing by qPCR with CHD1F/CHD1R primers only. [ABSTRACT FROM AUTHOR]

Information on mortality rates and their causes in raptors and owls during the post-fledging dependency period (PFDP) and subsequent dispersal is essential for their more effective protection, including more efficient use of funds. Despite the importance of the above data, these data are not yet available for most birds of prey. The study aimed to provide and expand the knowledge in this field for saker falcon. We used satellite telemetry to monitor a total of six young birds since they left the nest boxes. All young birds survived the PFDP, but none survived to adulthood and died during the period of dispersal movements. The PFDP lasted 47 days (median value hereinafter), and the distance of individuals from the nest boxes during this period was 3.2 km (maximum distance 9 km). The area of the home range of the PFDP calculated by the 100% minimum convex polygon (MCP) method was 81 km2. During the period of dispersal movements, the monitored individuals set up five temporary settlement areas with an area of 422 km2 according to 100% MCP, where they stayed for 37 days. All individuals’ mean length of movement routes throughout the monitoring period was 3862 km. The main finding of the present study is the fact that none of the monitored individuals survived the dispersal period. At least half of them died due to human activity (electrocution, hunting), which is probably unbearable in the long term for wild populations of most animal species. This shows the need to start eliminating all types of artificial traps (e.g., electrocution, hunting, poisoning, etc.) without delay, thus helping to prevent the decline of populations of many species in the shorter or longer time horizon.

A greater knowledge of the intrinsic and extrinsic factors of animal home range (HR) formation can help us to understand the fundamental biological issues underlying, for instance, movement patterns, habitat selection and survival. However, very little is known about the HRs of birds of prey fledglings, even though the post-fledging phase is recognised as crucial due to the high mortality of juvenile birds. We radio-tracked 138 Tengmalm's owl (Aegolius funereus) fledglings from 43 broods to determine their HRs during the post-fledging dependence period and to investigate the factors affecting their sizes. The study was conducted during four breeding seasons in Czechia and two seasons in Finland. The mean fledglings' HR size calculated according to the 95% IID Kernel Density Estimation method was 63.7 ± 43.9 ha (± SD; n = 71) during nocturnal activity and 52.0 ± 46.1 ha (n = 63) during diurnal roosting. The sizes of both nocturnal activity and diurnal roosting HRs increased with the longer individual duration of the post-fledging dependence period and also the higher rank of hatching within a brood. Diurnal roosting HRs were two times smaller in the Czech site, probably because of the very limited number of dense forest patches suitable for roosting as a legacy of the air pollution calamity in the 1970s, during which most coniferous stands died out. There was no difference in the size of nocturnal activity HR between the two study areas, although they differed markedly in terms of night length, altitude, weather, and forest age, structure and composition. This suggests that environmental factors are not decisive in determining the size of nocturnal activity HRs of Tengmalm's owl fledglings. Since the diurnal HRs always occurred within the area of the nocturnal HRs, we suggest that conservation of the densest and preferably oldest forest stands within the areas of the study species occurrence may offer straightforward conservation tasks for protecting Tengmalm's owl fledglings and also other species. [ABSTRACT FROM AUTHOR]

Summary: A considerable variety of Indonesian avifauna is forced into the domestic and international pet trade, where the majority of individuals are caught in the wild. To monitor the volume and development of the trade and to evaluate the threat status of the traded species, bird market surveys are usually performed. The most commonly used monitoring technique is the "Direct Counting Method – DCM", i.e. the counting of openly displayed individuals offered for sale. In this study, we evaluate the reliability of the outputs that DCM delivers by conducting regular long-term bird censuses at two of the main animal markets in Medan (Sumatra, Indonesia) involving 10 major local vendors specialising in the Sumatran Laughingthrush (Garrulax bicolor; SL), our target species. Both markets were visited from March to December 2015 with three different survey intervals (one, two and four visits per month). In total, according to DCM, we recorded up to 461 SL individuals offered for sale. However, a comparison of the monthly logs recorded directly by the vendors during the same period revealed that DCM only uncovered a negligible proportion of the total trade. Specifically, we detected only 4.6%, 8.1% and 16.1% of the traded SL individuals in relation to the set survey intervals. While the numbers of recorded SL individuals according to DCM and the three survey intervals were significantly interrelated, none of them correlated with the real numbers of traded birds provided by the vendors. Our results suggest that census-based market data are underestimated, and represent an unknown proportion of true trade volumes, regardless of the intensity of visits. In order to obtain reliable data and prevent the underestimation of the volume of trade, we recommend of undisclosed monitoring of markets and the engagement of trusted individuals with a past personal interest in this field or, if possible, the vendors themselves. [ABSTRACT FROM AUTHOR]

The behaviour of the nestlings of nocturnal cavity-nesting species has relatively rarely been studied in detail because of problems connected with use of the technical devices required to provide long-term monitoring of individuals. However, long-term observation of nestling behaviour is crucial in order to identify different types of behaviour which may be caused by sibling competition at the end of nesting period. We studied behaviour of 43 Tengmalm's owl (Aegolius funereus) nestlings at 14 nests using a camera and a chip system. The nestlings perched at the nest box entrance from an average age of 28 days from hatching (range 24–34 days) until fledging, spending around 2 hours per day here in total, in periods ranging from a few seconds to 147 min (7.6±10.9 min, mean ± SD). We found that individual duration of perching at the nest box entrance was significantly influenced by nestlings' age and wing length and that the duration of perching at the nest box entrance significantly decreased with time of night. However, during daylight hours, time of day had no effect on either probability or duration of nestlings' perching. We suggest daylight perching at the nest box entrance results from nestlings' preparation for fledging, while individuals perching here during the night may gain an advantageous position for obtaining food from the parents; another possibility at all times of day is that nestlings can reaffirm their social dominance status by monopolizing the nest box entrance. [ABSTRACT FROM AUTHOR]

Begging behaviour of nestlings has been intensively studied for several decades as a key component of parent-offspring conflict. There are essentially two main theories to account for intensity of food solicitation among offspring: that intensity of begging is related to some form of scramble competition between nest mates or that it offers honest signalling of need to parents. The vast majority of studies which have addressed begging behaviour have been based on observations of, and experiments on, nestlings and have not considered begging behaviour, during the post-fledging period. Begging vocalizations in this post-fledging phase of dependence have rarely been studied, despite the importance of vocalizations as a communication method between offspring and parents, particularly for nocturnal species. We radiotracked 39 fledglings of the Tengmalm’s owl (Aegolius funereus) in two years with different availability of prey: 2010 (n = 29 fledglings) and 2011 (n = 10 fledglings) and made 1320 nightly localizations in which we recorded presence or absence of begging calls. Within years, the most important measures related to the probability of vocalization were body condition at fledging, time of night, number of surviving siblings, age and weather conditions. Begging intensity increased with age in both years; however, in the year with low prey availability fledglings vocalized significantly more often. The main factor causing these differences between years was probably the different availability of prey, affecting breeding success, post-fledging behaviour, and thus also both short- and long-term needs of offspring. We believe that our results suggest honest signalling of their fledgling’s need. [ABSTRACT FROM AUTHOR]

Fledgling behaviour and movement patterns throughout the post-fledging dependence period (PFDP), especially in relation to changing environmental conditions, have been rarely studied, despite the fact that this period is recognized as of crucial significance in terms of high mortality of juveniles. The PFDP can extend over quite a protracted period, particularly in birds of prey, and a knowledge of the movement patterns of individuals is fundamental for understanding mechanisms underlying survival, habitat use and dispersion. We radiotracked 39 fledglings of the Tengmalm’s owl (Aegolius funereus) in two years with different availability of prey: 2010 (n = 29) and 2011 (n = 10) and obtained 1455 daily locations. Fledglings reached independence on average in 45 days after fledging in 2010 (n = 22) and 57 days in 2011 (n = 6). Within years, the most important measures influencing the distance moved from the nest box were age of fledglings and number of surviving siblings present. Individual home range size and duration of PFDP in particular were dependent on maximal number of siblings seen outside the nest box. In the season with low prey availability fledglings were observed at greater distances from the nest box than in the year with higher prey availability (mean distance: 350 m in 2010 and 650 m in 2011) and occupied larger home ranges (mean: 30.3 ha in 2010 and 57.7 ha in 2011). The main factor causing these differences between years was probably the different availability of prey in these two years, affecting breeding success and post-fledging survivorship of the Tengmalm’s owls. [ABSTRACT FROM AUTHOR]