In Hungary, during the 2000s, pesticide poisoning became the most important threat for raptors, especially for the globally threatened Eastern imperial eagle (Aquila heliaca). In September 2013, with a focus on carbofuran and phorate, the first poison and carcass detection dog (PCDD) unit was formed in Hungary with a specifically trained detection dog and handler. Two more dogs were subsequently trained and joined the unit in 2017 and 2020 respectively. Between its inception until August 2020, the PCDD unit conducted 1,083 searches in five countries, which revealed 329 poisoned animals of 15 bird and nine mammal species, 120 poisoned baits and five pesticide products. Globally threatened species, including eight Eastern imperial eagles and four saker falcons (Falco cherrug), were among the detected victims. Present at 66.45% of wildlife poisoning events, the unit revealed 37.87% of the victims and 79.70% of the poisoned baits known in Hungary during the period 2013-2020. Compared to human surveys, the PCDD unit demonstrated a significantly higher find rate for poisoned baits. At 22 poisoning events (14.38% of all cases) only the PCDD unit revealed victims or poisoned baits; cases that would probably have gone undetected without the PCCD unit. Of the two focal pesticides, carbofuran was more frequently detected – in 88.56% of the positive samples. The unit played a significant role in detecting and combating wildlife poisoning incidents by deterring potential offenders and facilitating police investigations through retrieval of evidence otherwise difficult to obtain.

La exposición a los pesticidas es una de las amenazas de mayor alcance para las aves rapaces. Recopilamos datos sobre envenenamiento de aves rapaces en 22 países europeos, abarcando 3196 incidentes de envenenamiento reportados que afectaron a 4437 aves rapaces envenenadas de 37 especies entre 1996 y 2016. Las aves rapaces más comúnmente envenenadas fueron carroñeras obligadas o facultativas, pero su contribución proporcional al número total de rapaces envenenadas varió de un país a otro. Los ratoneros, las águilas, los buitres y los milanos juntos representaron el 85% de las aves rapaces envenenadas. Sobre un total de 4437 aves rapaces, Buteo buteo (46%), Gyps fulvus; (12%), Haliaeetus albicilla (9%), Milvus milvus (7%) y Circus aeruginosus (5%) fueron las más frecuentemente afectadas por los pesticidas. De las especies documentadas, seis están amenazadas a nivel mundial y 15 están disminuyendo a nivel mundial según la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza. En total, se detectaron 41 pesticidas de forma independiente, y 34 pesticidas combinados. Se notificaron carbofuranos y aldicarb en el 55% y el 14%, respectivamente, de las aves rapaces envenenadas con detección de una sola sustancia, y en el 57% y el 18% de las aves rapaces envenenadas con múltiples sustancias. Más de la mitad de las aves rapaces envenenadas con carbofurano y aldicarb se reportaron después de las prohibiciones comerciales de estas sustancias. El carbofurano fue el veneno más comúnmente detectado en cuatro grupos de aves rapaces con diferentes dietas. De 1589 aves rapaces envenenadas con carbofurano como sustancia única, el 88% fueron categorizadas como carroñeras facultativas. Los casos de envenenamiento con fechas conocidas alcanzaron su punto máximo en marzo–abril, con el 37% de las 3566 aves rapaces envenenadas durante este tiempo. El envenenamiento de carroñeros facultativos alcanzó su punto máximo en marzo–abril, mientras que la estacionalidad del envenenamiento en otras rapaces estuvo menos claramente definido. Concluimos que el uso generalizado de plaguicidas que afectan a las aves rapaces en Europa y la gama asociada de especies afectadas sugieren que pueden haber implicaciones para la reducción de los servicios ecosistémicos que estas aves proveen. [Traducción del equipo editorial]

The Saker Falcon (Falco cherrug) is a globally threatened bird species, and Hungary hosts the second-largest population in Europe. The Hungarian population most likely reached its historical minimum by the 1970s, with an estimated number of 15–30 breeding pairs. Intensive monitoring and conservation efforts began in 1980 through the cooperation of MME BirdLife Hungary and the national park directorates. In this paper, we present the long-term natural history of the Hungarian Saker Falcon population from 1980 to 2024. Throughout the study period, both range expansion and breeding population size exhibited an increasing trend. The number of known territorial pairs grew at an average annual rate of approximately 8%. The population reached its historical maximum in 2024, when 200 territorial pairs were recorded, of which 177 successfully bred, producing 530 fledglings. A total of 4,429 breeding attempts were monitored in Hungary over 45 years, of which 3,467 were successful, yielding 10,319 nestlings. The breeding performance parameters of the population showed a generally stable trend with slight fluctuations throughout the study period. The annual mean (±SD) success rate was 0.76 (±0.14), and the mean brood size was 2.94 (±0.29), resulting in an overall productivity of 2.26 (±0.49). Following the socio-economic changes in Hungary in the 1990s, the breeding population of Saker Falcons shifted its range from the mountains to the lowlands. This shift was driven by decreased persecution of raptors, habitat changes and the subsequent decline in the availability of key prey species in the foothills. Between 1986 and 2015, 24,882 identifiable prey items of Saker Falcons were recorded, belonging to 164 different taxa. Diet analysis revealed that four species played a particularly significant role in the diet of Saker Falcons in Hungary: Feral Pigeon (Columba livia f. domestica) , European Ground Squirrel (Spermophilus citellus) , Common Starling (Sturnus vulgaris) , and Common Vole (Microtus arvalis) . Although Columbiformes remained the most common prey group, their abundance did not show a significant trend. In contrast, the proportion of Passeriformes increased significantly. A more pronounced change was observed among mammals in the diet. The previously common European Ground Squirrel declined dramatically, while the proportion of other Rodentia and Lagomorpha species increased significantly. The growth of the Hungarian Saker Falcon population halted after 2010. However, a slight increase has been observed in recent years (2018–2024), raising the hope that a gradual recovery may still be possible in the coming decades.

Survival rate is usually the greatest contributor to population growth in long‐lived species, and its accurate estimation along with the evaluation of the factors influencing it is therefore essential for effective conservation. Here, we studied the survival of breeding eastern imperial eagles Aquila heliaca in Hungary between 2011 and 2022 and investigated the effect of poisoning, the leading known anthropogenic cause of mortality. We used the Cormack‐Jolly‐Seber mark‐recapture model to estimate annual apparent survival and encounter probabilities based on the capture histories of 208 males and 411 females. We obtained encounter data from the DNA profiles of shed feathers collected at the nest sites, which we also supplemented with presences inferred from parentage analysis. The most supported model estimated a constant 91.6% annual survival over the study period, but models including the effect of sex and poisoning rate on survival had similar support. Sex difference in survival was less than 1% on average, but the survival of males decreased more with poisoning rate than the survival of females. However, due to smaller encounter probabilities, the estimates for males were less precise compared to females. Males may be more at risk from poisoning than females not only due to their more active foraging behaviour during incubation and chick‐rearing but also due to their smaller body size. Apart from providing direct practical information for the conservation management of imperial eagles, our results also highlight the importance of long‐term studies for estimating population parameters of birds of prey.

Natal dispersal plays an important role in the ecological and evolutionary processes of a species and has major implications for its conservation. Here, we studied natal dispersal patterns in the Pannonian population of the vulnerable eastern imperial eagle Aquila heliaca in regard to sex, local density, and dispersal direction. We defined local density at each nest as the reciprocal of the area of the Thiessen polygon drawn around the nest. Using the combined methods of colur‐ringing, GPS tracking, and DNA profiling, we managed to determine natal dispersal distances for 116 chicks (43 males, 72 females, 1 with unknown sex) hatched in Hungary between 2012 and 2020. Eagles were highly philopatric, with all 116 individuals settling in the Pannonian population and only 4.3% of them emigrating from the eastern to the western subpopulation. Natal dispersal distance was female‐biased (median: 57.6 km for females and 35.9 km for males). In general, birds settled at lower‐density sites compared to their natal site but moved to higher‐density sites from natal sites with low density. During the exponential population growth in the second period of the study, females dispersed mainly in a southern direction, towards low‐density areas. Our results demonstrate that natal dispersal patterns in the imperial eagle are sex‐dependent and are shaped by both intraspecific competition and conspecific attraction. The observed high philopatry implies the genetic uniqueness of the Pannonian population, making it of high conservation value.