Recruitment Rates, Natal and Breeding Dispersal of Montagu’s Harriers (Circus Pygargus) by Means of Microsatellite Analysis

Autumn migration routes of two Dutch female Montagu’s Harriers (Circus pygargus) were documented for the first time using satellite telemetry. Both migrated to their African wintering area—one via the Straits of Gibraltar through the Mediterranean and the other via Italy/Tunisia. The rate of travel was comparable to values reported for larger raptor species.

The ground nesting raptor Montagu’s Harrier breeds in loose colonies in cereal fields in the Spanish Extremadura. It is unclear how and whether birds in different colonies interact and how harriers spend time before and after nesting, before starting migration. We used GPS–GSM tags deployed on ten females and three males, some over multiple seasons, to follow bird movements with unprecedented detail. Arriving from spring migration, all males and most females returned to their old nest site, and spent between 13 and 25 days in mate choice and local site inspection. During incubation and early nesting female movements were strongly reduced, but increased significantly during late nesting and post-fledging periods. After fledging or after breeding failure, females increased their flying radius. Some of them visited other colonies, for single days or for longer periods, or flew long distances within Spain. These visits might have included help in breeding attempts of other pairs (adoptions). Four out of six females returned to their own breeding site before starting migration. Several females repeatedly used common roosts in this phase. Non-breeding females were active in defending nests in the colony against predators. Females with successful brood initiated migration earlier and spent less time in Spain than non-breeders or those with predated nests. Unlike females, daily distances in males were more uniform. While all males remained in the breeding area for the entire season, their activity centres shifted more within that area than those of females.

Dispersal is an important life history trait with significant consequences for spatially structured populations, as the exchange of individuals between habitat patches is crucial for maintaining metapopulation connectivity. In this study, we used a long-term data set (2005–2023) to describe dispersal patterns in a patchy population of the Western Yellow Wagtail Motacilla flava within a large (approximately 1,300 km2) study area in the boreal zone of European Russia. We quantified dispersal distances for birds that dispersed outside their natal or breeding habitat patches and applied a multistate capture–recapture approach to estimate natal and breeding dispersal probabilities. Of 395 adult wagtails and 1,610 nestlings ringed, 3% of birds ringed as adults and 3% of birds ringed as nestlings were resighted outside their natal or breeding patches. The probability of natal dispersal (0.29 ± 0.05) was significantly higher than the probability of breeding dispersal (0.05 ± 0.01). The median natal dispersal distances (2.8 km for males, 3.9 km for females) were the same as the median breeding dispersal distances (2.7 km for males, 3.9 km for females). We did not find a significant effect of the fledging date on either the natal dispersal distance or the natal dispersal probability. Similarly, we did not find a significant effect of the previous reproductive success on either the breeding dispersal distance or the breeding dispersal probability. Our results indicate that strong breeding site fidelity and short-distance natal dispersal are the dominant dispersal strategies in a patchy population of the western yellow wagtail.

Distances between nest-sites used successively within a breeding season were measured in a population of Stonechats. The frequencies and consequences of dispersing different distances were examined in relation to previous nesting success. Nestpredation tended to be greatest after moving far from the previous nest site, and was no higher after predation on the previous nest, but was low if many young had fledged. Nestling growth was significantly better at greater distances from the previous nest, if young had fledged from it. Birds moved farther, and were more likely to use different vegetation in which to nest, after previous predation than if success had been low for other reasons. After escaping predators, they moved farther, and were more likely to change vegetation, if more young had fledged from the previous nest. These results imply that birds adjust the placement of nests according to previous success, though great variation in dispersal distance remained unexplained by these tactics.

Dispersal is a fundamental process with wide‐ranging evolutionary and management consequences. To date, natal dispersal has never been described for the polygynous‐promiscuous European hareLepus europaeus. Using telemetry, we investigated the natal dispersal pattern in two zones that differed in hunting pressure and hare density. We quantified both the natal dispersal rates and distances using 84 juvenile hares. We tested for the influence of several factors (age, sex, density and period of the year) on these two variables. Overall, the mean dispersal rate was 43% and the median natal dispersal distances were 209 m for philopatric hares and 1615 m for dispersers. The maximum distance moved was 17.35 km. Natal dispersal rates were higher in the hunting zone with less density for both males and females, but males dispersed more frequently than females in the two zones although females moved over longer distances. Natal dispersal occurred preferentially between 4 and 6 months of age. This very fine description of the natal dispersal pattern allowed us to make inferences about both the evolutionary and proximate causes of natal dispersal. We also advocate that more attention should be paid to dispersal in studies on hare dynamics and on the conception of hare management, because dispersal seems to be more common than previously thought.

This report presents the first complete natal dispersal trajectory of a female Montagu’s Harrier Circus pygargus, tracked in real time from fledging to first breeding using high-resolution continuous Global Positioning System (GPS) telemetry. The bird’s first flight occurred on 26 July 2024, initiating a 31-day post-fledging dependence phase (PFDP), followed by a 23-day pre-migratory phase (PMP), during which it explored areas up to 280.8 km from the nest and eventually settled ca. 190 km away in the Sirente-Velino Regional Park. From there, autumn migration began on 18 September 2024. The bird reached its first wintering site in Mali by 15 October. It used four wintering areas over 178 days, with a winter home range of 37,615.02 km2. Spring migration started on 11 April 2025 and lasted 21 days, ending with arrival in the Gran Sasso e Monti della Laga National Park (Central Italy) on 2 May. The bird used two main sites during the pre-breeding phase (PRBP) before laying eggs on 2 June 2025. The natal dispersal distance, from birthplace to nest site, was 151.28 km. Over 311 days, it covered a total of 14,522.23 km. These findings highlight the value of advanced telemetry in revealing early-life movement ecology and are useful for understanding species-specific patterns of survival, reproduction, and space use and can inform conservation actions.

The studies of species composition and abundance of diurnal birds of prey may be quite indicative of the state of natural ecosystems and of the level of impact of human-induced factors on their functions. Such studies are particularly important within the protected areas taking into account unfavourable conservation status of many species of the group. The status, abundance, aspects of habitat distribution and breeding habitat preferences of diurnal birds of prey were studied within national nature park ‘Dvorichanskyi’ and adjacent territories (750 sq. km, Dvorichanskyi district, Kharkiv Region, Ukraine) in 2010–2018. 22 species were registered. The breeding of six species was confirmed e.g. Black Kite (Milvus migrans), Marsh Harrier (Circus aeruginosus), Goshawk (Accipiter gentilis), Sparrowhawk (Accipiter nisus), Common Buzzard (Buteo buteo), Booted Eagle (Hieraaetus pennatus). The breeding of four more species is considered probable namely Honey Buzzard (Pernis apivorus), Montagu’s Harrier (Circus pygargus), White-tailed Eagle (Haliaeetus albicilla) and Hobby (Falco subbuteo). There are indications of possible breeding of Short-toed Eagle (Circaetus gallicus) and Kestrel (Falco tinnunculus). The rest of the species are migrating and/or wintering. The most numerous breeding species is Common Buzzard. The abundance of Booted Eagle is comparatively high that discerns the study area from other parts of Kharkiv Region. 40 nests of birds of prey were carefully inspected. The majority were found in ravine steppe forests (83%). Oak, alder and willow flood-plain forests are very important breeding habitats for Black Kite and Booted Eagle while ravine steppe forests are those for Goshawk, Sparrowhawk, Common Buzzard and Booted Eagle. Pedunculate oak (Quercus robur) is the most favourable tree species for building the nests (47.5% of all inspected nests) followed by European ash (Fraxinus excelsior) (15%) and European pear (Pyrus communis) (10%).

We investigated the departure, transient movement, and local settlement stages of natal dispersal in a population of Northern Goshawks (Accipiter gentilis) on the Kaibab Plateau of northern Arizona. The study included 614 color-banded juveniles produced at 555 nests during 1991–2003, 89 of which were radio-marked during 1998–2001. Radio-marked juveniles initiated dispersal between 71 and 103 days posthatching, and spent between 33 and 66 days in the natal territory after fledging. Our best-fitting proportional hazards models predicted the timing of dispersal as a function of annual differences in the density of primary bird and mammal prey species, weather conditions, and natal brood size. Once dispersal was initiated, most juveniles moved into the more open habitats that surrounded the study area and few eventually returned to breed; first-year fidelity to the local natal population was 28%, and only 69 (11%) color-banded juveniles had entered the territorial population by 2004. Median natal dispersal distance on the Kaibab Plateau was 15.0 km (range = 0.1–58.1 km), a distance equivalent to about four times the diameter of an average breeding territory (3.8 km). Local settlement behavior of Northern Goshawks appeared to be driven by a combination of intraspecific competition for a limited number of breeding opportunities and inbreeding avoidance. However, much of the natal dispersal process operated at broad spatial scales beyond our study population, indicating a potentially high level of demographic connectivity among naturally fragmented breeding populations in the American Southwest.

Natal dispersal is of central interest when determining demography and genetic structure of populations and managing endangered species with fragmented distributions. However, methodological limitations linked to spatial and temporal constraints have prevented studies of natal dispersal in long-lived birds. Moreover, the consequences of natal dispersal have mainly been related to the first breeding attempt rather than to lifetime reproductive success. We studied the causes and fitness consequences of natal dispersal in a population of Black Kites at Donana National Park (southern Spain). From 1986 to 1995 we marked 2929 nestlings with plastic numbered bands. We annually monitored marked birds in breeding territories, their breeding success, and the survival of nonbreeding birds. Additionally, we searched for marked birds in broad areas of the Iberian Peninsula and North Africa. Median natal dispersal distance was 4.8 km (N = 285), with males more often dispersing shorter distances and females dispersing at all distance categories equally. Density of conspecifics negatively affected dispersal distances of both males and females. In addition, single and first-hatched males born in areas with high breeding density dispersed shorter distances. Dispersal distances tended to be correlated between siblings, possibly a result of sharing similar environmental conditions. We did not find evidence that dispersal was an active mechanism aimed to prevent close inbreeding. Patterns of dispersal in this population are probably driven by intraspecific competition. Males that dispersed shorter distances showed higher lifetime reproductive success (LRS). LRS did not differ among females dispersing different distances, but females that dispersed farther mated with more experienced males. These sex differences in dispersal patterns and their consequences may be explained by the inequality between sexes in breeding roles in this species. Familiarity with the natal area could be important for males, which defend territories and resources, while females may increase their fitness through mate choice and breeding dispersal. High levels of philopatry in Donana National Park may be a result of a surplus of food resources and the effects of conspecific attraction in densely populated areas. However, the degree of philopatry may vary between populations and with time, subject to differences in ecological pressures.

Natal dispersal is a fundamental component of the ecology and evolutionary history of birds, yet is often prohibitively difficult to study. We characterized natal dispersal for the first time in a bird using molecular genetic parentage analyses in a tropical rainforest understory species, the chestnut‐backed antbird (Thamnophilidae:Myrmeciza exsul). Median natal dispersal distance was ∼800 m (mean = 931 ± 84 (SE) m, n = 48), with ∼90% of all distances < 1500 m. We found no evidence of sex‐biased dispersal. An index of self‐recruitment (i.e. individuals establishing a territory within the population of origin) was higher in sites largely or entirely surrounded by non‐forest, suggesting birds are reluctant to disperse out of preferred forest habitat. Via simulations, we confirmed that the genetic data had sufficient resolution to correctly identify parent‐offspring dyads, but lacked resolution to identify other relationships (full‐sib and half‐sib) with confidence. Chestnut‐backed antbirds have measurable self‐recruitment rates caused by short natal dispersal distances, and self‐recruitment may be amplified by reluctance to disperse out of sites bordered by non‐forest. Some tropical forest understory birds have naturally short dispersal distances, and our results have implications for understanding how species will be affected by fragmented landscapes and for the design of reserves.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 126:145-152 (1995) - doi:10.3354/meps126145 Slow population turnover in the soft coral genera Sinularia and Sarcophyton on mid- and outer-shelf reefs of the Great Barrier Reef Fabricius KE Aspects of the life history of the 2 common soft coral genera Sinularia and Sarcophyton were investigated on 360 individually tagged colonies over 3.5 yr. Measurements included rates of growth, colony fission, mortality, sublethal predation and algae infection, and were carried out at 18 sites on 6 mid- and outer-shelf reefs of the Australian Great Barrier Reef. In both Sinularia and Sarcophyton, average radial growth was around 0.5 cm yr-1, and relative growth rates were size-dependent. In Sinularia, populations changed very slowly over time. Their per capita mortality was low (0.014 yr-1) and size-independent, and indicated longevity of the colonies. Colonies with extensions of up to 10 x 10 m potentially could be several hundreds of years old. Mortality was more than compensated for by asexual reproduction through colony fission (0.035 yr-1). In Sarcophyton, mortality was low in colonies larger than 5 cm disk diameter (0.064 yr-1), and significantly higher in newly recruited small colonies (0.88 yr-1). Photographic monitoring of about 500 additional colonies from 16 soft coral genera showed that rates of mortality and recruitment in the family Alcyoniidae differed fundamentally from those of the commonly more 'fugitive' families Xeniidae and Nephtheidae. Rates of recruitment by larval settlement were very low in a majority of the soft coral taxa. The general assumption that soft corals are fast-growing pioneers does not apply to the Alcyoniidae on the central Great Barrier Reef, where their life history traits indicate great persistence. Octocorallia . Alcyoniidae . Sinularia . Sarcophyton . Life history traits . Growth . Mortality . Recruitment Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 126. Publication date: October 05, 1995 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1995 Inter-Research.

Context Optimal management of invasive species should determine the interval between lethal-control operations that will sustain a desired population suppression at minimum cost. This requires an understanding of the species’ rate of recruitment following control. These data are difficult to acquire for vertebrate carnivores such as the red fox (Vulpes vulpes), which are not readily trapped or observed. Aims To provide a long-term evaluation of the effects of 1080 poison baiting on the abundance and extent of movement of red foxes in a semiarid environment. Methods We used non-invasive DNA sampling of fox hairs in semi-arid Western Australia where the population was subject to two episodes of aerially delivered sodium fluoroacetate (1080) poison baits within 12 months. Sampling took place at ~45-day intervals and individual foxes were identified by genotyping eight microsatellite DNA markers and a gender-specific marker. Open-population and spatially explicit mark–recapture models were used to estimate the density, apparent survival and movements of foxes before and following baiting. Key results Following a severe reduction in density after baiting, fox density during the ensuing 12 months increased slowly (0.01 foxes km–2 month–1), such that density had only reached 22% of pre-baiting levels ~10 months after the initial baiting. Moreover, recovery was non-linear as population growth was negligible for 6 months, then exhibited a nine-fold increase 7–9 months after control, coincident with the dispersal of juveniles in autumn. Fox movements between recaptures were on average 470% greater after baiting than before, in line with expectations for low-density populations, suggesting that the probability of encountering baits during this period would be higher than before baiting. Conclusions Baiting with 1080 poison significantly reduced the density of foxes, and the low density was sustained for more than 6 months. Foxes moved significantly further between recaptures after baiting when at low densities. Implications Control programs in this region may be carried out at low frequency to suppress fox density to a fraction of unbaited levels. The intensity of follow-up baiting may also be adjusted downwards, to take account of an increased probability of bait encounter in more mobile foxes.

Natal dispersal is an important component of bird ecology, plays a key role in many ecological and evolutionary processes, and has important conservation implications. Nevertheless, detailed knowledge on natal dispersal is still lacking in many bird species, especially raptors. We review and compile existing information from five tagging programmes of juvenile Montagu's harriers (Circus pygargus) in different Spanish regions, with PVC rings or wing tags, to provide an assessment of philopatry and natal dispersal of the species in Spain. Only 7% of all tagged harriers were observed as breeders in subsequent years. The percentage of philopatric (i.e. breeding within 10 km of the natal site) males and females was lower that 5%. Overall, there were no sexual differences in percentage of philopatric birds or dispersal distances, but we found study area differences. The low philopatry observed suggests a high capacity for natal dispersal in this species, for both sexes, and therefore high genetic mixing between populations. Differences in philopatry between study areas may be influenced by the different observation effort or detectability, or else reflect different philopatric strategies among populations. Finally, we found no significant differences in philopatry rate or dispersal distances related to tagging method, suggesting that tagging technique has a smaller effect than monitoring effort or observation ease on observation probability. Developing tagging programmes at a small scale and without procuring very large-scale and intensive subsequent monitoring is not worthwhile for evaluating philopatry and natal dispersal in this species.

Exploration as a key component of natal dispersal: dispersers explore more than philopatric individuals in roe deer

During the last decades the ground-breeding Montagu’s harrier (Circus pygargus, Linnaeus, 1758) has changed its breeding habitats in Europe to agricultural areas in which many local populations would be close to extinction without a special nest protection regime. Although Montagu’s harrier is a well-studied species in terms of ecology and breeding biology, its genetic structure and population genetics are almost unknown. As there is a lack of good genetic markers we developed a set of 19 microsatellite markers comprising 16 new STR markers which were identified by next-generation sequencing (NGS) using 454 shot-gun pyrosequencing of genomic DNA. The STR markers were arranged into three multiplex PCR sets for high throughput genotyping and characterised. The marker set provides a powerful tool for kinship analysis. The combined non-exclusion probability for parent pairs was 1.13*10-11. Only three loci showed PIC values < 0.50. In total, 121 known family relationships were compared with genetically calculated ones to test the markers suitability for parentage analysis. In 97.5% of all cases full-sibships were accurately determined and 97.6% of all mothers were assigned correctly to their chicks. The present multiplex PCR panels can be used to investigate several hypotheses concerning breeding behaviour, kinship, exchange rates between populations and phylogeography.