Numerous regions worldwide are affected by Earth climate warming. Most studies of bird phenology in relation to global and regional climate change have focused on trends in arrival dates and breeding ...dates. The study investigates the results of phenological spring migration research on Eurasian Golden Oriole during a period of 26 years (1991–2016) in relation to average spring air temperatures (April–May) and year in deciduous forests (northwestern Croatia). Data is available for spring arrivals detected by the first song. Arrival date advanced significantly during the research period. According to the linear regression slopes, models suggested that in Eurasian Golden Oriole arrival date has advanced 6 days in period 1991–2016. Furthermore, average spring air temperatures (April–May) increased significantly during the study period. Furthermore, date of arrival was significantly negative correlated with average spring temperatures. My results provide evidence that warms spring has impacted spring migration arrival dates of Eurasian golden oriole of the deciduous forests in northwestern Croatia.
Klimatsko zatopljenje dokumentirano je na mnogim područjima Zemlje. Mnogi znanstveni radovi o utjecaju klimatskih promjena na ptičji svijet ponajprije se odnose na fenologiju, a u prvom redu na povratak ptica sa zimovanja i početak nesidbe jaja. U ovome članku prezentiraju se rezultati 26-godišnjeg (1991-2016) praćenja proljetne migracije vuge u bjelogoričnim šumama na području sjeverozapadne Hrvatske u odnosu na prosječne proljetne temperature travnja i svibnja (razdoblje povratka sa zimovanja). Podaci su se prikupljali na temelju prvog glasanja vuge pojedine godine. Dobiveni rezultati sugeriraju da se vuge vraćaju šest dana ranije u odnosu na početnu godinu istraživanja. U spomenutom istraživačkom razdoblju osim što se vuge na području gniježđenja pojavljuju sve ranije, istodobno je došlo do signifikantnog porasta prosječnih temperatura travnja i svibnja. Zabilježena je značajna negativna korelacija između datuma povratka i prosječnih proljetnih temperatura, što nas upućuje na zaključak da su sve toplija proljeća vjerojatno razlogom sve ranijeg povratka vuge sa zimovanja u bjelogorične šume sjeverozapadne Hrvatske.
Large-scale international monitoring studies are important to assess emission patterns and environmental distributions of organohalogenated contaminants (OHCs) on a worldwide scale. In this study, ...the presence of OHCs was investigated on three continents (Europe, North America and Australasia), using eggs of starlings (Sturnus vulgaris and Sturnus unicolor) to assess their suitability for large-scale monitoring studies. To the best of our knowledge, this is the first study using bird eggs of the same species as a biomonitor for OHCs on an intercontinental scale. We found significant differences in OHC concentrations of the eggs among sampling locations, except for hexachlorocyclohexanes (HCHs). Mean concentrations of sum polychlorinated biphenyls (PCBs) in eggs ranged from 78±26ng/glipid weight (lw) in Australia to 2900±1300ng/glw in the United States. The PCB profile was dominated by CB 153 and CB 138 in all locations, except for New Zealand, where the contribution of CB 95, CB 101 and CB 149 was also high. The highest mean sum polybrominated diphenyl ether (PBDE) concentrations were found in Canada (4400±830ng/glw), while the lowest mean PBDE concentrations were measured in Spain (3.7±0.1ng/glw). The PBDE profile in starling eggs was dominated by BDE 47 and BDE 99 in all countries, but in Belgium, the higher brominated PBDEs had a higher contribution compared to other countries. For the organochlorine pesticides (OCPs), dichlorodiphenyltrichloroethanes (DDTs) ranged from 110±16ng/glw in France to 17,000±3400ng/glw in New Zealand, while HCHs and hexachlorobenzene were generally in low concentrations in all sampling locations. Chlordanes were remarkably high in eggs from the United States (2500±1300ng/glw). The OCP profile in all countries was largely dominated by p,p′-DDE. In general, the worldwide trends we observed in starling eggs were in accordance with the literature on human and environmental OHC data, which suggests that there is potential for using starling eggs as a biomonitoring tool on a large geographical scale.
► Organohalogenated contaminants (OHCs) were studied in European starling eggs from 3 continents. ► Concentrations and profiles differed significantly among the sampling locations. ► The geographical distribution of OHCs reflected the expected emission patterns. ► OHC worldwide trends were in accordance with data from human and environmental samples. ► Starling eggs have potential as a biomonitoring tool on a large geographical scale.
Conservation of the biodiversity of the forest ecosystems is becoming one of the priority issues in the forest management. Birds play an important role in the overall life of the forest ecosystem, ...for instance, as an important component of the trophic chains. Recent studies worldwide suggest decline in the population size and richness of the forest bird species, especially those nesting in the cavity of the forest trees. Special emphasis is placed on the secondary cavity nesters. In contrast to the primary cavity excavators, which are making a tree cavity by themselves, secondary cavity nesters for their nesting use cavities made by the primary cavity excavators or natural cavities formed by gradual wood decay process. In order to maintain bird diversity in the forests with a lack of nesting cavities, installation of the nestboxes is an important strategy in many countries. This applies mainly to young deciduous, coniferous stands, and monocultural plantations and areas afforested with exotic tree species. In this paper, occupation of the nestboxes in the young deciduous stands was investigated. According to some researchers, the colour of the nestbox and its height above the ground could be important factors of the nestbox occupation in some bird species. In this study, a total of 120 standard wooden nestboxes were used (60 green and 60 brown). Nestboxes were installed in pairs on a single tree, at a height of 4.0 to 4.5 m (“high” position) and 2.0 to 2.5 m (“low” position). On the first tree, the green nestbox was in the “high” position, on the next tree in the “low” position and so on. The aim of this study was to determine the degree of occupancy of the nestboxes with a respect to the colour and the position on the tree. Because of the intra- and interspecific competition, only one of the nestbox pair was inhabited. Of the total 60 nestbox pairs, 44 (73.3%) nestboxes were occupied; 35 (79, 5%) by a Great Tit (
Parus major
) and 9 (20.5%) by a Blue Tit (
Cyanistes caeruleus
). Great Tits occupied mainly “green” nestboxes (88.6%), with no significant differences in the height position of the chosen nestbox. In conclusion, the colour of the nestboxes is more important factor than the height position on the tree during the occupation of the nestboxes by a Great Tit.
U gospodarenju i upravljanju šumama sve se više nameće kao prioritetno pitanje očuvanje bioraznolikosti šumskih ekosustava. Ptice imaju značajnu ulogu u cjelokupnosti živoga svijeta šuma, primjerice, kao važna sastavnica hranidbenih lanaca. Recentna istraživanja diljem mnogih regija svijeta upućuju na pad populacija i bogatstva šumskih ptičjih vrsta, a to se posebice odnosi na ptice koje se gnijezde u dupljama šumskog drveća. Poseban je naglasak na sekundarnim dupljašicama. Za razliku od primarnih ptica dupljašica koje same dube šupljine u drvetu (deblu ili granama), sekundarne dupljašice za gniježđenje koriste duplje primarnih dupljašica ili duplje nastale prirodnim propadanjem drveta. Da bi se održala raznolikost ptičjeg svijeta u šumama bez dovoljno duplji za reprodukciju, u sve se više zemalja pristupa postavljanju umjetnih duplji (škrinjica). To se ponajviše odnosi na mlade bjelogorične, crnogorične i monokulturne sastojine te područja pošumljena egzotičnim vrstama. U ovome se radu analizira jedno takvo vješanje škrinjica u mladoj bjelogoričnoj šumi. Neka istraživanja sugeriraju da u nekih vrsta ptica u naseljavanju škrinjica određenu važnost ima obojenost te visina škrinjica iznad tla. U ovome istraživanju ukupno je postavljeno 120 standardnih drvenih škrinjica (60 zeleno obojenih i 60 smeđe obojenih) za veliku sjenicu (
Parus major
). Škrinjice su vješane u parovima na pojedino drvo, na visinu 4,0 – 4,5 m („visoko“ ) i 2,0 – 2,5 m („nisko“). Na prvom bi drvetu „zelena“ bila na poziciji „visoko“, na drugom drvetu na poziciji „nisko“ i tako redom. Cilj ovog rada bio je utvrditi stupanj prihvaćanja škrinjice s obzirom na obojenost te poziciju na drvetu. Od 60 parova škrinjica naseljene su 44 (73,3%). Od para škrinjica na drvetu ptice bi naselile samo jednu zbog intra- i interspecijske kompeticije. Od 44 naseljene škrinjice velika sjenica naselila je 35 (79, 5%), a plavetna sjenica (
Cyanistes caeruleus
) devet (20,5%). Velika je sjenica najvećim dijelom naselila „zelene“ škrinjice (88,6%) dok s obzirom na poziciju škrinjica na drvetu nije bilo značajne razlike. Zaključno, tijekom naseljavanja škrinjica boja ima prednost u odnosu na poziciju škrinjice na drvetu.
Many authors have discussed use of birds (and other organisms) as sensitive biomonitors for climate change. In this paper we investigate the long-term trends in first arrival dates of the ...long-distance migratory House Martin, Delichon urbica (Linneus, 1758), in north-western Croatia during the 28-year period. The aim of this paper is to identify possible relationship between arrival times and local spring air temperatures. Between 1981 and 2008 the House Martin arrived progressively earlier (5.9 days), probably in response to climate change. First arrival dates correlated significantly with increasing March-April mean temperatures. Correlation between mean spring air temperature and yearly temperatures were also statistically significant. Our results suggest that the arrival timing of the House Martin is influenced by spring air temperatures
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