Intraspecific nest parasitism has only recently received more attention from ornithologists. In 2001, Yom-Tov published a list of 234 species that had exhibited this behaviour. I have since found literature data on four additional species in which intraspecific nest parasitism has been observed. No such record has so far been published from Hungary. This study presents records on 25 species from Hungary and on one species from Croatia, out of which I have not found any reference for intraspecific nest parasitism in the literature for Cattle Egret (Bubulcus ibis), Eurasian Thick-knee (Burhinus oedicnemus), Black-winged Stilt (Himantopus himantopus), Collared Pratincole (Glareola pratincola), Mediterranean Gull (Larus melanocephalus), Little Tern (Sternula albifrons), Whiskered Tern (Chlidonias hybrida), Eurasian Roller (Coracias garrulus) and Eurasian Jackdaw (Corvus monedula). In addition to records from Hungary, for Black-headed Gull (Larus ridibundus) and Mediterranean Gull I also present observations from Slovakia, and for Common Shelduck (Tadorna tadorna) from Germany.
There are numerous publications in the ornithological literature on mixed-species broods, i.e. on cases when a species lays some or all of its eggs into the nests of other species. This phenomenon, known as brood parasitism, has not yet been studied in Hungary. Here, I use the term brood parasitism, but I could not separate cases of egg dumping, a reproductive error by females. Based on literature and my own observations, I found evidence for interspecific brood parasitism in 28 species breeding in Hungary, not including the cases of the obligate interspecific brood parasite, the Common Cuckoo (Cuculus canorus). Only one of these belongs to passerines, while in the rest of the cases, this phenomenon occurred in representatives of non-passerine families. However, cases of brood parasitism and nest parasitism have to be treated separately. The latter refers to cases when a species occupies a nest, usually a nesthole or nestbox, already containing eggs of another species, and lays its own eggs next to the foreign eggs. The present study provides data on European Roller (Coracias garrulus), Northern Goshawk (Accipiter gentilis), Common Kestrel (Falco tinnunculus), Red-footed Falcon (Falco vespertinus), Eurasian Hobby (Falco subbuteo), tit species (Parus, Cyanistes, Poecile spp.), Eurasian Nuthatch (Sitta europaea) and Eurasian Tree Sparrow (Passer montanus), but in all likelihood the number of species involved is much higher.
Based on data available so far, it seems that Common Moorhens (Gallinula chloropus) rarely, but regularly lay one or more eggs in the nests of Common Little Bittern (Ixobrychus minutus). Three such incidents from Hungary are hereby added to the cases known to date. However, Common Moorhens do not only lay eggs in other species’ nests, but also in the nests of conspecifics, while other species may also parasitise the nest of Common Moorhens. The present study summarises these aspects.
In this study, the results of a long-term nest box installation program of the Common Barn-owl Tyto alba (Scopoli, 1769) in Southern Hungary were evaluated, which program was conducted during a 24-year period (1995–2018). The percentages of occupied nest boxes ranged from 9.72 to 73.44% in the first breeding periods while this varied between 0 and 41.46% in the case of repeated clutches in the same nest boxes with second broods. A total of 1,265 breeding attempts were recorded including 1,020 (80.63%) in the first and 245 (19.36%) in the second breeding periods, from which a total of 210 (16.6%) clutches did not produce any fledglings. The modal clutch size was 7 eggs in both first and second annual clutches. However, the value of productivity was higher in the case of larger clutch sizes and we found significant linear relationship between initial clutch size and fledgling production per nesting attempt in both breeding periods. Significant variation of reproductive parameters was observed among the years. The proportion of egg loss showed significant decline, while the change of hatching success and the variation of annual productivity showed significant slight positive linear trend during the 24 years. Our results suggested that despite the outlier values of reproduction characteristics in the extreme years with negative effect, a relatively stable Common Barn-owl population can be maintained by the placement of nest boxes in the investigated region.
The diet composition of breeding Eastern Imperial Eagles (Aquila heliaca) was analysed in Hungary between 2005 and 2017, and compared with two previously published datasets from the periods of 1982–1991 and 1992–2004. Altogether the distribution of 8543 prey items of 126 different species and 29 other taxa were analysed within a 36-years period. We found that the previously abundant Common Hamster (Cricetus cricetus) became marginal (7.42%), while European Sousliks (Spermophilus citellus) practically disappeared (0.03%) from the diet of Imperial Eagles. Small game species, like the Common Pheasant (Phasianus colchicus) and the Brown Hare (Lepus europaeus) composed a remarkable part of the diet (11.22% and 28.11% respectively), which raised some conflicts with hunters regionally and probably also contributed to the high prevalence of persecution incidents against the eagles. In parallel with the loss of traditional prey species, corvids (13.10%), pigeons (8.90%), waterbirds (6.83%), other rodents (6.71%), Roe Deers (Capreolus capreolus) (5.59%), raptors and owls (4.88%) became regularly detected prey species. The temporal changes of the main prey categories were analysed between 1998 and 2017, when the ratio of Hamster and Pheasant showed significant decrease (-27.29% and -6.38%, respectively). The ratio of Brown Hare also showed slight decrease (-3.98%), but the change was not significant. On the other hand, the ratio of corvids, waterbirds and Roe Deers within the diet showed significant increase (+18.20%, +6.25% and +5.39%, respectively). The observed flexibility in the foraging behaviour of Imperial Eagles greatly facilitate conservation efforts, as they seems to be able to utilize the most abundant prey sources, i.e. they were not depending solely from the status of any single specific prey source. However, eagles could only shift and survive in those regions, where their traditional preys decreased, if alternative species were available for them.
Bird conservation on electricity transmission lines has a 40-year history in Hungary. It started with the saker conservation program. The initial small-scale activities were considerably enlarged through the LIFE projects. In the first project, 301 nest boxes for sakers of a new type made of aluminium were installed on pylons of high-voltage transmission lines. In 201 3 nearly 70% of saker pairs nested in these new boxes. An estimated 1 00 000 different birds used to be killed annually on the transmission line pylons in Hungary. During the two LIFE projects about 1 4 300 pylons were made bird-safe using improved technology and materials. Nearly 800 new bird-safe crossarms of pylons are being installed in the second project, which is expected to completely eradicate the danger