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Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Surprisingly, prospecting in active breeders occurs in 85.7% of studied species, and contradicts theoretical models that showed that prospecting is expected to evolve in a relatively predictable and stable environment. Prospecting is more common in populations with frequent inter-annual changes of breeding sites, in species that evolved in ephemeral habitats and among females. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and predict its consequences on fitness at the individual and population levels.

Gulls, as migratory wild birds are known that can spread different pathogens over long distances. Aim of this study was to access prevalence of different Listeria species in their population fed at the Zagreb landfill site. Altogether, 390 gulls of three species were sampled: Yellow-legged Gull, Larus michahellis; Black-headed Gull, L. ridibundus and Common Gull, L. canus. Most prevalent species was L. innocua (14.4%), while L. monocytogenes was found in 11.3 % of tested samples. The presence of other species was found in a smaller percentage, namely L. welshimeri (1.3%), L. ivanovii (0.5%) and L. seeligeri (0.3%). Serotyping of L. monocytogenes isolates was performed using both molecular and conventional methods, and most isolates belonged to serotypes 1/2a and 1/2b. To the best of our knowledge, this study reports the first results of research on the presence of L. monocytogenes and other Listeria spp. in wild birds in Croatia.

The present study assessed the effect of agricultural practices on biomarker response in white stork (Ciconia ciconia) nestlings from continental Croatia. During the breeding season of 2022, blood was sampled (n = 54) from the landfill Jakuševec and the agricultural areas Baranja and Srijem. Different patterns of biomarker response in regard to the sampling site were detected. Results demonstrate the presence of inhibitory pollutants from the landfill Jakuševec and agricultural area Baranja, which is reflected in lower cholinesterase (ChE) activity. Oxidative stress biomarkers show different responses concerning study sites. Glutathione reductase (GR) activity was higher in Baranja and Srijem, suggesting a different mixture of pollutants inducing an antioxidative response. Leachate from the landfill Jakuševec is suspected to affect the white stork nestlings by elevating the concentrations of reactive oxygen species (ROS). An environmental combination of pollutants appears to induce oxidative stress in white stork nestlings. In addition to agricultural practices, white stork nestlings may also be under environmental pressure from the surrounding pollution. Further research is warranted to include additional chemical analysis to associate the environmental concentrations with the potential adverse effects in apex predators, such as the white stork.

Campylobacteriosis represents a global health challenge due to continuously increasing trends of antimicrobial resistance in Campylobacter jejuni. C. jejuni can sometimes cause life-threatening and severe systematic infections (bacteremia, meningitis, and other extraintestinal infections) with very few antibiotics left as treatment options. Bearing in mind that C. jejuni is the predominant species in humans, in this paper, we present a study of the C. jejuni differences in antimicrobial resistance and genotype distribution between strains isolated from stool and primary sterile sites. We compared the genomic data obtained through whole genome sequencing (WGS) and phenotypic susceptibility data of C. jejuni strains. Once antimicrobial susceptibility testing of C. jejuni strains was carried out by the broth microdilution method for six of interest, results were compared to the identified genotypic determinants derived from WGS. The high rate of resistance to fluoroquinolones presented in this study is in accordance with national surveillance data. The proportion of strains with acquired resistance was 71% for ciprofloxacin and 20% for tetracycline. When invasive isolates were analysed separately, 40% exhibited MIC values of ciprofloxacin higher than the ECOFFs, suggesting a lower flouroquinolone resistance rate in invasive isolates. All isolates demonstrated wilde-type phenotype for chloramphenicol, erythromycin, gentamicin, and ertapenem. A special focus and review in this study was performed on a group of C.jejuni strains found in primary sterile samples. Apart from demonstrating a lower resistance rate, these isolates seem genetically more uniform, showing epidemiologically more homogenous patterns, which cluster to several clonal complexes, with CC49 being the most represented clonal complex.

This study aimed to assess the presence of thermotolerant

Campylobacteriosis represents a global health challenge due to continuously increasing trends of antimicrobial resistance in

White stork nestlings can provide quantitative data on the quality of the environment, as they are dependent on their parents that provide locally foraged food. Blood was sampled from the brachial vein (n = 109) and the sampling was performed in parallel with ringing during breeding season 2020 from five areas in eastern Croatia: Lonjsko polje, Jelas polje, Slavonski Brod-east, Podunavlje, and Donje Podravlje. In the present study, for the first time in Croatia, the following enzymatic biomarkers were assessed in white stork nestlings: activities of acetylcholinesterase (AChE), carboxylesterase (CES), glutathione S-transferase (GST), and glutathione reductase (GR), as well as nonenzymatic biomarkers: levels of glutathione (GSH) and reactive oxygen species (ROS). All endpoints were measured in two blood fractions: plasma and a postmitochondrial fraction (S9). Nestlings from Podunavlje and Donje Podravlje, areas known for intensive agriculture, showed lower AChE and CES activity when compared to the other investigated areas, indicating the presence of inhibitory xenobiotics. Higher oxidative stress was observed in Slavonski Brod-east, an area surrounded by metal and engineering industry, and Podunavlje compared to the other sampling areas. Hence, this study shows the impact of pollutants from the surrounding metal, petroleum, and agricultural industry might have on the biomarkers in white stork nestlings, which are often seen as early-warning signals.

Between 2002 and 2019, monitoring of Common Tern Sterna hirundo and Little Tern Sternula albifrons along the Sava River near Zagreb, Croatia was conducted. Natura 2000 site “Sava kod Hrušćice” was designated to protect colony at river islands, with estimated population sizes of 100–150 pairs of Common and 20 pairs of the Little Tern. Flooding of the colony caused breeding failure in several years. Common Terns moved to breed on islands in gravel pits with a total population around 150 pairs, while Little Tern did not breed after 2010. In the last few years, terns have not bred at Hrušćica and the only colony inside the Natura 2000 site is situated on a breeding platform at Siromaja gravel pit. Channelling of rivers and hydropower plants are the main threats, changing natural dynamics of water level and causing reduction of gravel sediment in rivers.

Morphometric data on Common Terns breeding in Croatia and Slovenia are presented herewith for the first time. 130 breeding adult Common Terns Sterna hirundo were measured between 2016 and 2019 along the Sava and Drava Rivers. Sex was determined for 53 birds: 22 males and 31 females. Significant sexual differences were found for head and bill length, length of bill to skull, and bill depth. Croatian and Slovenian terns had slightly shorter wings and tails compared to birds from the Netherlands, Germany and England and were lighter than birds from Germany and Italy. Head, bill and tarsus lengths were similar to those in north European populations. Contrary to results from Scotland, in our studied population, birds with head and bill lengths >79.0 mm could not be sexed as males reliably.

This study aimed to assess the presence of thermotolerant Campylobacter spp., as one of the most important foodborne zoonotic pathogens, in three shellfish species: mussels (Mytilus galloprovincialis), oysters (Ostrea edulis) and queen scallops (Aequipecten opercularis). The samples were collected from nine locations in the Istrian aquatory, Croatia. Isolation of Campylobacter was done according to standard ISO method, and species were identified using multiplex PCR. Isolates identified as C. jejuni and C. lari were genotyped using multilocus sequence typing (MLST) to determine the potential source of contamination. Among 108 examined samples of bivalve molluscs, mussels dominated and were the only ones found positive for the presence of Campylobacter (25.6%). In total, 19 C. lari and 1 C. jejuni strains were isolated. C. lari isolates found in this study belong to 13 sequence types (STs), and 9 of them are newly described in this paper. Two out of the four previously described C. lari STs that were found in this study were previously found in human stool. The only C. jejuni isolate was found to be sequence type 1268, which belongs to ST-1275 clonal complex that is almost exclusively found in seabirds and can sporadically cause infection in humans. Regarding the obtained results, introducing surveillance of thermotolerant Campylobacter in shellfish in the Republic of Croatia is advised as an improvement for public health safety.

Zagorski puran kao hrvatska autohtona pasmina sa zaštitom zemljopisnog podrijetla i zaštićenom oznakom izvornosti sve se više uzgaja na obiteljskim poljoprivrednim gospodarstvima. Tradicionalni način držanja zagorskog purana na otvorenom, uz često nedovoljno prostora u objektima kao i izmetom, hranom i otpadom često zaprljani manji ispusti, način hranjenja uz neodržavanje higijene hranilica i pojilica i uzgoj raznovrsne peradi na istom prostoru, u prvom redu kokoši, predispozicija su za pojavu bolesti poput mikoplazmoze i histomonijaze. U takvim uvjetima česta je i sekundarna bakterijska infekcija bakterijom Escherichia coli. U radu smo dali osnovne smjernice uzgoja zagorskog purana, kao i pregled najznačajnijih bolesti kojima pogoduje tradicionalni način uzgoja zagorskog purana ustvrđenih tijekom dvogodišnjeg istraživanja na obiteljskim poljoprivrednim gospodarstvima Krapinsko- zagorske županije. Praćeno je ukupno 46 uzgoja s preko 10000 uzgojenih purana godišnje. U 22 % obiteljskih poljoprivrednih gospodarstava ustvrđen je zarazni sinusitis, a u 11 % uzgoja histomonijaza. Sekundarna bakterijska infekcija bakterijom E. coli dokazana je u 10 uzgoja zahvaćenih mikoplazmom ili histomonijazom. Povećanom uginuću i štetama u gospodarstvima vjerojatno je pridonijela i učestala, nasumična, nekontrolirana i nepotrebna uporaba antimikrobnih lijekova koji stvaraju rezistenciju bakterija. Uz zaštitu zagorskog purana kao hrvatskog izvornog proizvoda, od velike je važnosti provoditi i sustavni veterinarski nadzor kako bi se prevenirao razvoj bolesti te unaprijedio i povećao uzgoj ove važne hrvatske peradi., The Zagorje turkey, as an indigenous Croatian breed with protection of geographical origin and protected designation of origin, is being bred in increasing numbers on family farms. The traditional outdoor way of keeping Zagorje turkey is predisposed for the occurrence of diseases, such as mycoplasmosis and histomoniasis, due to the often insufficient space in facilities and in small outlets often dirty from faeces, food and waste, and based on a feeding method without maintaining the hygiene of feeders and drinkers, with the simultaneous breeding of other poultry species (chickens primarily). Under such conditions, secondary bacterial infection with Escherichia coli is also common. This paper provides basic guidelines for breeding the Zagorje turkey, and gives an overview of the most significant diseases arising in the traditional breeding of Zagorje turkey, based on the results of a two-year study on family farms in Krapina-Zagorje County. A total of 46 farms with over 10,000 raised turkeys per year were monitored. Infectious sinusitis was found in 22% of family farms, and histomoniasis in 11%. In 10 farms, affected by mycoplasmosis or histomoniasis, secondary infection with Escherichia coli was also proven. Frequent, random, uncontrolled and unnecessary use of antimicrobial drugs not only gives rise to bacterial resistance, but likely also contributed to increased mortality and damages on farms. Systematic veterinary supervision is highly important to protect the Zagorje turkey as a Croatian original product, and also to prevent the development of diseases and improve and increase the breeding of this important Croatian poultry.

Due to SARS CoV-2 recombination rates, number of infected people and recent reports of environmental contamination, the possibility of SARS CoV-2 transmission to animals can be expected. We tested samples of dominant free-living and captive wildlife species in Croatia for the presence of anti-SARS CoV-2 antibodies and viral RNA. In total, from June 2020 until February 2021, we tested blood, muscle extract and fecal samples of 422 free-living wild boars (Sus scrofa), red foxes (Vulpes vulpes) and jackals (Canis aureus), blood and cloacal swabs of 111 yellow-legged gulls (Larus michahellis) and fecal samples of 32 zoo animals. A commercially available ELISA (ID.Vet, France) and as a confirmatory test, a surrogate virus neutralization test (sVNT, GenScript, Netherlands) were used. Fecal samples were tested for the presence of viral RNA by a real-time RT–PCR protocol. Fifteen out of 533 (2.8%) positive ELISA results were detected, in wild boars (3.9%), red foxes (2.9%) and jackals (4.6%). However, the positive findings were not confirmed by sVNT. No viral RNA was found. In conclusion, no spillover occurred within the investigated period (second COVID-19 wave). However, further investigation is needed, especially regarding wildlife sample features for serological tests.

The Caspian Gull is a breeding species of eastern Europe and central Asia, whose breeding range has over the last 100 years been expanding to western parts of Europe. It is regularly seen on migration and wintering in Croatia. Since the historical literature data for Larus cachinnans in Croatia mainly refer to the Yellow-legged Gull, the aim of this research was to determine the origin of Caspian Gulls wintering in Croatia. Recoveries from the Prudinec rubbish dump in Zagreb and the ones obtained from the ringing archive of the Institute of Ornithology, Croatian Academy of Sciences and Arts have been analysed. Ringed individuals seen in Croatia belong to the populations from central and eastern Europe, and the first ringed individual from the Black Sea population has been recorded. Compared to the available literature data, four new countries of origin of Caspian Gulls seen in Croatia have been recorded: Lithuania, the Czech Republic, Hungary, and Romania. The longest distance from the place of recovery (Croatia) to the place where the individual has been ringed (Ukraine) is 1507 kilometres. Ringed individuals were recorded in Croatia from October to March., Pontski galeb je gnjezdarica središnje i istočne Europe te središnje Azije čiji se areal recentno širi prema zapadu Europe. U Hrvatskoj je zabilježen kao preletnica i zimovalica. Budući da se literaturni podaci za pontskog galeba u Hrvatskoj najčešće odnose na galeba klaukavca, cilj ovog rada bio je utvrditi porijeklo pontskih galebova koji zimuju u Hrvatskoj, odnosno na kojem području se gnijezde te kojoj populaciji pripadaju. Analizirani su nalazi pontskih galebova u Hrvatskoj od 2001. do 2021. godine s odlagališta otpada Prudinec u Jakuševcu te nalazi dobiveni iz Arhive prstenovanja Zavoda za ornitologiju HAZU. Gotovo sve prstenovane jedinke pontskih galebova zabilježenih u Hrvatskoj pripadaju populacijama srednje i istočne Europe s Poljskom kao državom porijekla najvećeg broja jedinki te Njemačke s porijeklom najmanjeg broja jedinki. Također, zabilježena je i prva jedinka, prstenovana u Rumunjskoj, koja pripada populaciji pontskih galebova s Crnog mora. U odnosu na dostupnu literaturu, zabilježene su četiri nove države porijekla pontskih galebova viđenih u Hrvatskoj: Litva, Češka, Mađarska i Rumunjska. Najveća zračna udaljenost od mjesta nalaza jedinke do mjesta prstenovanja iznosi 1507 kilometara (odlagalište otpada Prudinec u Jakuševcu, Zagreb – Solonyi Lyman Lake, Dnipropetrovsk Oblast, Ukrajina). Prstenovane jedinke su viđene od listopada do ožujka, a najveći broj prstenovanih jedinki pontskih galebova zabilježen je tijekom prosinca, siječnja i veljače. Mlade jedinke su u Hrvatskoj bilježene od listopada dok su odrasle jedinke bilježene od studenog. Ovaj rad doprinosi poznavanju fenologije pontskog galeba u jugoistočnoj Europi budući da status taksona u susjednim državama (Italija, Slovenija, Srbija, Bosna i Hercegovina, Crna Gora) i državama šire regije (Albanija, Sjeverna Makedonija, Grčka, Bugarska) nije detaljno proučavan.

Campylobacteriosis is the most common gastrointestinal bacterial disease in the European Union (EU). Wild birds are one of the natural reservoirs of these pathogens. In this study we tested cloacal swabs of 643 gulls captured on rubbish tip in Zagreb, Croatia for the presence of Campylobacter spp. and found 168 Campylobacter positive samples. We used multilocus sequence typing (MLST) to genotype 62 random C. jejuni isolates from gulls, 24 isolates from broiler caeca, 27 isolates from broiler neck skins and 23 human isolates. Altogether, we identified 44 different STs, from which 19 were newly described. Most of the new STs (14) originate from gulls. Although humans and broilers share the majority of STs and isolates from gulls are separated from these, there was one ST present in all three hosts: 45. Additionally antimicrobial susceptibility to six antimicrobials was performed on 123 C. jejuni strains isolated from broiler caeca (n = 22), neck skins of broilers (n = 20), gulls cloacal swabs (n = 50) and human faeces (n = 31) by the broth microdilution method. Results show lower resistance of gull isolates to NAL and CIP, while resistance to TET was as high as in human and broiler isolates.

Background The majority of European Common Terns (Sterna hirundo) migrate south along the western coast of Europe and Africa, while birds from eastern regions are known to cross the Mediterranean Sea from east to west or migrate along the eastern African coast. The migration route of north European terns wintering along the coast of western Africa was already described using geolocator data, while knowledge about movements of the European inland populations is based only on relatively scarce recoveries of ringed birds. Methods We used light-level geolocators in inland Common Tern colonies in Hungary and Croatia to study their migration route and to identify wintering areas along with stopover sites. Results revealed by geolocators were compared with recoveries of ringed birds. Results All tracked birds used the east African migration route with autumn stopovers at Lower Nile and in the southern part of the Red Sea, and short spring stopover in Israel. Terns wintered along Kenyan coasts and in the southern Mozambique Channel. Autumn migration lasted four times longer than spring migration. Conclusions This is the first geolocator study that describes the east African migration route of the Common Tern. Important stopover sites were identified. More studies of inland populations are needed to better elucidate tern winter movements.

During the breeding periods of 2018 and 2019 we investigated the extent of areas Common Terns Sterna hirundo use while searching for food. We used GPS-UHF tags to follow the movements of 23 terns from Slovenia (7 individuals) and Croatia (16 individuals). We investigated the movements of birds from three breeding sites, i.e. Lakes Ptuj, Siromaja 2 and Rakitje. Conclusions are based on 43,105 locations which were collected with a frequency of one reading per 20 minutes during the day and one reading per 4 hours during the night. In Slovenia, terns used a 60 km long and narrow area over Stara struga Drave (former river-bed of the Drava River) between Ormož and Maribor as well as eleven fishponds / lakes in its surroundings, most of them in the Pesnica valley. The most distant location was 30 km of straight line from breeding islands, but it was visited only once by a single tern. The areas with the most locations, hence important areas, were Lake Ptuj, Drava at Ptuj, Stara struga Drave between Ptuj and Rošnja and about 20 km distant Lakes Radehova and Gradiško. These were probably the most important feeding areas for Common Terns breeding on Lake Ptuj. In Croatia, terns were found along the Sava almost exclusively, with only a few visits more than 2 km from the river. The most distant locations were over 60 km away from the breeding grounds, but terns visited them only rarely. Most locations of terns nesting on Siromaja were within a 5 km radius, while terns from Rakitje were making regular flights to waters up to 23 km from their colony. The area with the most locations visited by terns from both colonies was the Sava at Hrušćica. Besides, birds from the Rakitje colony were frequently recorded on the Sava near Savica and waterbodies within 5 km of the colony. These were probably the most important feeding areas for Common Terns breeding around Zagreb.

63 Common Tern Sterna hirundo samples from Croatia and Slovenia were analysed with respect to their genetic diversity and differentiation. Samples originated from two freshwater populations (areas of the rivers Sava and Drava) and one coastal population (Sečovlje Salina). The molecular marker of choice was 709 bp long fragment of the mitochondrial control region, the fastest-evolving part of the mitochondrial genome. 21 haplotypes with 12 polymorphic sites were identified. Overall haplotype diversity was substantial and estimated at 0.8599, while the overall nucleotide diversity was low and estimated at 0.0025. Diversity indices were highest for the Drava population, followed by the Sava and the lowest for the Sečovlje population. Overall genetic structure was significantly low (Fst=0.0377) and attributed to the differences in haplotype frequencies between the populations. The high level of genetic diversity found in continental populations illustrates the importance of their habitats as reservoirs of genetic diversity and calls for their further protection and management.

With increasing advances in telemetry technology, prospecting behaviour was identified in many seabirds ; mostly in immatures, but also in adults – during pre- breeding and post-breeding periods and among failed breeders. However, prospecting has not yet been documented among active breeders. We equipped 17 Common terns Sterna hirundo with GPS-UHF data-loggers and tracked their movements during late incubation and chick rearing in continental Croatia. We monitored the fate of their clutches until chicks left the nest. Birds of both sexes visited other breeding colonies within relatively short distances, while they still had active nests. These results confirm for the first time the presence of prospecting trips during incubation and chick-rearing in active breeders. Such behaviour probably developed because quick and unpredictable changes in their freshwater habitats can cause failure of whole colonies, forcing them to renest at other sites during the same breeding season. Prospecting during the first breeding attempt might shorten the renesting interval, and increase renesting success when multiple breeding sites are available on an easily accessible area. With increasing vulnerability of colony sites due to climate change, studies of scattered colonies are needed to better understand renesting and adult prospecting strategies.

In 2018 and 2019, the breeding success of two Common Tern colonies on artificial lakes near the River Sava in Zagreb, Croatia, was studied. The colonies were visited weekly from May to July and we collected data on phenology, number of breeding pairs, clutch size as well as egg and chick survival. We also conducted a comparison between early and late breeders. Hatching and fledging success was within previously observed ranges, apart from a low hatching success on Siromaja in 2019. The smaller colony on Siromaja had a higher productivity in both years than the colony on Rakitje, although in 2018 an avian pox virus killed much of the late chicks on Rakitje. Early breeders seem to have had higher hatching success and average clutch size. Furthermore, a greater proportion of them managed to hatch all their eggs compared to late breeders, but the differences were not statistically significant. Our study provided baseline data for future monitoring of phenology and breeding success with regard to the management of breeding colonies.

The Audouin's Gull Larus audouinii is endemic to the Mediterranean, with the majority of the global population concentrated in Spain. It mainly feeds on small pelagic fish during the night; however, there is more variation in the foraging behaviour of the Ebro Delta population, with birds also feeding during the day and inland. This plasticity was identified as one of the main factors involved in the increase in population size since 1980. However, foraging movements have only been poorly studied in other populations. We studied the movements of Audouin's Gulls breeding in the small, endangered Croatian population, foraging at the Adriatic Sea, and compared their behaviour with that of conspecifics in the increasing Spanish population in Ebro Delta. Five incubating adults were equipped with a GPS-GSM solar-powered tracking device. We analysed characteristics of short and long foraging trips, differences in movement patterns between sexes and between night and daytime, and the association of gulls with fishing vessels. Daily average trip lengths were similar for all birds, while individual patterns were very diverse. Birds undertook both short (up to 45 km) and long-distance trips (up to 256 km), with length of trips, trip duration and the maximum distance being greater for females. The comparison of gull GPS-fixes with tracking data (VMS) of purse seine fishing vessels showed that birds from the Croatian population, in contrast to the Spanish birds, did not associate with fishing vessels, nor did their foraging behaviour change as an effect of a fishing moratorium. Our results showed that long-distance movements were longer and more frequent than those recorded in other populations, which suggests that depending on non-anthropogenic resources may result in a high cost of chick-rearing.

Campylobacteriosis is the most common gastrointestinal bacterial disease in the European Union (EU). Wild birds are one of the natural reservoirs of these pathogens. In this study we tested cloacal swabs of 643 gulls captured on rubbish tip in Zagreb, Croatia for the presence of Campylobacter spp. and found 168 Campylobacter positive samples. We used multilocus sequence typing (MLST) to genotype 62 random C. jejuni isolates from gulls, 24 isolates from broiler caeca, 27 isolates from broiler neck skins and 23 human isolates. Altogether, we identified 44 different STs, from which 19 were newly described. Most of the new STs (14) originate from gulls. Although humans and broilers share the majority of STs and isolates from gulls are separated from these, there was one ST present in all three hosts: 45. Additionally antimicrobial susceptibility to six antimicrobials was performed on 123 C. jejuni strains isolated from broiler caeca (n = 22), neck skins of broilers (n = 20), gulls cloacal swabs (n = 50) and human faeces (n = 31) by the broth microdilution method. Results show lower resistance of gull isolates to NAL and CIP, while resistance to TET was as high as in human and broiler isolates.

Capsule: In Yellow-legged Gull Larus michahellis populations from the eastern Adriatic Sea, there are considerable differences in the ratio of migratory birds and apparent survival among the colonies. Survival was dependent on age, colony and area of dispersal. Aims: To identify the ratio of migratory birds within populations of Yellow-legged Gulls, and to compare apparent survival of gulls during migration in central and northern Europe and around the Adriatic Sea. Methods: We analysed 15 years of resighting data of Yellow-legged Gulls using a MARK multi-state model to calculate survival rates. The effects of age, natal colony and area of dispersal were examined. Results: Almost 60% of Adriatic Yellow-legged Gulls were migratory but the ratio varied among colonies (10.3–78.3%). Survival was dependent on age, colony and area of dispersal, with average values per group ranging between 0.599 (se 0.093) and 0.684 (se 0.084). Conclusion: The ratio of migratory and dispersive Yellow-legged Gulls from different Adriatic colonies might be affected by both inheritance and food availability.

U radu je opisana pojavnost bakterija roda Salmonella koje ne stvaraju sumporovodik izdvojenih iz navlaka za obuću i fecesa tovnih pilića te kože vratova i svježeg mesa peradi. U 2016. godini u laboratorijima Hrvatskoga veterinarskog instituta izdvojeno je ukupno 25 ovakvih izolata za koje je dokazana pripadnost serovarovima koji uobičajeno posjeduju sposobnost tvorbe sumporovodika: 24 izolata serovara Infantis te 1 izolat serovara Typhimurium. Prema dostupnim literaturnim podacima, ovo je prvi opisani slučaj izdvajanja bakterija roda Salmonella koje ne proizvode sumporovodik izoliranih iz peradi izvan Azije, a pripadaju serovarovima koji ga uobičajeno tvore.

Bakterije mikroorganizmi koji za svoj rast u okolišu, kao i u laboratorijskim uvjetima trebaju mikroaerofilne uvjete. Za rutinsku analitiku klasičnim metodama primjerena je primjena priznatih standardiziranih protokola i propisanih visoko selektivnih tekućih i/ili krutih hranjivih podloga. Nakon porasta karakterističnih kolonija radi određivanja vrste kampilobaktera primjenjuju se mikroskopski, fenotipski, biokemijski, imunozimski testovi, rezistotipizacija i/ili metoda masene spektrometrije. Za razlikovanje sojeva kampilobaktera postoje dvije klasične metode serotipizacije. Do sada je razvijen znatan broj PCR protokola usmjerenih prema otkrivanju Campylobacter roda, vrste ili podvrste, bilo iz uzoraka hrane, okoliša ili izmeta. Glavne prednosti PCR metoda su u njihovoj brzini, osjetljivosti i specifičnosti, a nedostatak PCR metodologije je u tome što ne razlikuje žive od mrtvih stanica, zbog čega se razvijaju novi protokoli bazirani na RT-PCR, NASBA i QRT- PCR molekularnim metodama., Bacteria of the genus Campylobacter require microaerophilic conditions for growth. Use of recognized standardized protocols and prescribed highly selective liquid and/ or solid media is appropriate for routine analysis with classical methods. After the growth of characteristic colonies, microscopic, phenotype and biochemical methods, immunoenzyme tests, resistotypization and/ or mass spectrometry are applied to determine the Campylobacter species. Two classical serotyping methods are used to differentiate Campylobacter strains. There are various PCR protocols intended for the detection of Campylobacter genus, species or subspecies from food samples, environment or faeces. The main advantages of PCR methods are their speed, sensitivity and specificity. The deficiency of this method is that it does not differentiate viable from dead cells, therefore new protocols based on RT-PCR, NASBA and QRT-PRC molecular methods are under development.

In the fourth report of the Croatian Birds Rarities Committee, new accepted records of rare birds that were submitted to the committee in the period 2012-2016 are reported. Ten species, of which one is treated as escape from captivity, and two subspecies have been observed in Croatia for the first time. The list of birds of Croatia now holds 396 species in categories A, B and C, and 5 species in category C E. Further 11 species are recorded in category E and one in category D, and these are not included in the list of birds of Croatia. Three species have been removed from the rare birds list due to the increasing number of their observations. The list of rare bird taxa now includes 72 species, of which 5 are included in category C E, and 4 subspecies. Additional eleven species are treated as escapees (category E) and one as probable escapee (category D)., Četvrti izvještaj Hrvatske komisije za rijetke vrste ptica donosi prihvaćena opažanja rijetkih vrsta i podvrsta ptica koja je komisija zaprimila u razdoblju 2012-2016. Deset vrsta ptica, od kojih je jedna odbjegla iz zatočeništva, te dvije podvrste u Hrvatskoj je zabilježeno po prvi put. Popis ptica Hrvatske sada sadrži 396 vrsta zabilježenih u kategorijama A, B i C te 5 vrsta zabilježenih u kategoriji C E. Daljnjih 11 vrsta koje su zabilježene u kategoriji E i jedna u kategoriji D nisu uključene u popis ptica Hrvatske. Tri vrste su uklonjene s popisa rijetkih vrsta zbog povećane učestalosti njihovih opažanja u Hrvatskoj. Popis rijetkih vrsta sada obuhvaća 72 vrste i 4 podvrste u kategorijama A-D.

In the fourth report of the Croatian Birds Rarities Committee, new accepted records of rare birds that were submitted to the committee in the period 2012-2016 are reported. Ten species, of which one is treated as escape from captivity, and two subspecies have been observed in Croatia for the first time. The list of birds of Croatia now holds 396 species in categories A, B and C, and 5 species in category C E. Further 11 species are recorded in category E and one in category D, and these are not included in the list of birds of Croatia. Three species have been removed from the rare birds list due to the increasing number of their observations. The list of rare bird taxa now includes 72 species, of which 5 are included in category C E, and 4 subspecies. Additional eleven species are treated as escapees (category E) and one as probable escapee (category D).

U radu se opisuje sluþaj infekcije bakterijom Erysipelothrix rhusiopathiae u konzumnih nesilica hibridne linije Tetra SL, dobi 60 tjedana. Kliniþki znaci bolesti u jatu oþitovali su se smanjenom nesivosti i poveüanim uginuüem, što je trajalo desetak dana. Patoanatomske promjene bile su kaheksija, izražena cijanoza sluznica, kože glave i vrata, znakovi sepse, hiperemiþni tumor slezene, poveüenje i punokrvnost jetre te u jednom sluþaju nekroza jetre i upala jajnika i jajovoda. Bakteriološkom pretragom je iz sve þetiri pretražene jetre, tri slezene i dva ovarija izdvojena vrsta Erysipelothrix rhusiopathiae. Izdvojena bakterija identificirana je biokemijskom karakterizacijom pomoüu API nizova Rapid ID 32 STREP. Testovi tvorbe katalaze i oksidaze kao i test na pokretljivost bili su negativni. U razmazima napravljenim iz þiste bakterijske kulture i obojanim prema Gramu naÿeni su savijeni i nitasti gram-pozitivni štapiüi. Prema rezultatima testa osjetljivosti vrsta Erysipelothrix rhusiopathiae pokazala je osjetljivost prema deset, a neosjetljivost prema tri antimikrobna lijeka.

U radu je opisana pojavnost bakterije Salmonella Infantis u uzorcima navlaka za obuću i fecesu tovnih pilića. U razdoblju od 2010. do 2014. godine u Laboratoriju za bakteriologiju Centra za peradarstvo Hrvatskog veterinarskog Instituta ukupno je pretraženo 18799 uzoraka. Ukupno je izdvojeno 357 bakterija iz roda Salmonella, od čega 81 serovara Infantis. U istraživanom razdoblju zabilježen je zamjetan rast izdvojenih salmonela, naročito serovara Infantis. U razdoblju od 2010. do 2013. godine serovar Infantis bio je drugi najčešće izdvojeni serovar, dok je 2014. bio najčešći. Ovakav trend vidljiv je i u Europskoj Uniji, kao i u mnogim državama svijeta. Mnogi autori kao mogući razlog ovako velikog porasta učestalosti serovara Infantis vide u novootvorenoj niši koja je nastala kao rezulat uspješne kontrole serovarova Enteritidis i Thyphimurium.

Afrička kukavica je rijetka gnjezdarica Hrvatske. Mlada afrička kukavica Clamator glandarius promatrana je 5. kolovoza 2014. kod mjesta Polače na otoku Mljetu. Radi se o najjužnijem promatranju ove vrste u Hrvatskoj. Daljnja istraživanja potrebna su radi potvrđivanja mogućeg gniježđenja na tom području.

A total of 142 black-headed gulls (BHGs), Chroicocephalus ridibundus, were captured during February and March 2009 at the Zagreb city rubbish dump (45.45 N 16.01 E) in order to collect cloacal swabs and serum samples. Cloacal swabs were tested by virus isolation in embryonated chicken eggs, which resulted in isolation of one avian influenza virus (AIV) that was of the H16 subtype. The collected sera were tested by blocking ELISA for avian influenza antibodies, resulting in 28.2% positive samples, which were retested by haemagglutination inhibition (HI) using H5 and H7 subtype antigens. Only one serum sample was positive for H5 and none for H7 antibodies. Statistically, no significant difference was found between the ages of AIV seropositive birds (2 = 2.08, df = 1, P = 0.15). In contrast, regarding seroprevalence in different months of capture, a higher proportion of positive gulls was found during March than during February (2 = 4.53, df = 1, P = 0.03), especially in younger birds (2 = 7.67, df = 1, P = 0.006). This finding suggests that BHGs might contract AIV infection during their aggregations in large numbers on rubbish dumps or similar feeding sites during the winter. Although only one of the 142 tested birds was positive for H5 subtype antibodies, this finding cannot be neglected seeing that apparently healthy BHGs can carry highly pathogenic AIV of the H5N1 subtype. Nevertheless, the results of our study have shown that BHGs are more often infected with other AIV subtypes and therefore are most likely not the primary carriers of H5 AIV. To our knowledge this is the first detection of H16 AIV in Croatia., Tijekom veljače i ožujka 2009. na gradskom odlagalištu otpada u Zagrebu (45.45 N 16.01 E) uhvaćena su 142 riječna galeba (Chroicocephalus ridibundus) u cilju prikupljanja brisova nečisnica i uzoraka krvi. Brisovi nečisnica su pretraženi izdvajanjem virusa u embrioniranim kokošjim jajima što je rezultiralo izdvajanjem virusa influence ptica koji je bio podtipa H16. Prikupljeni uzorci seruma su pretraženi imunoenzimnim testom za protutijela virusa influence ptica od kojih je 28,2% bilo pozitivno. Pozitivni uzorci su dodatno pretraženi inhibicijom hemaglutinacije s antigenima podtipa H5 i H7 među kojima je samo jedan bio pozitivan na H5 i nijedan na H7 protutijela. Statistički nije ustanovljena značajna razlika među skupinama različite dobi seropozitivnih ptica (2 = 2,08, df = 1, P = 0,15). Nasuprot tome, seroprevalencija u različitim mjesecima lova je imala veći udio tijekom ožujka nego tijekom veljače (2 = 4,53, df = 1, P = 0,03), naročito u mlađih ptica (2 = 7,67, df = 1, P = 0,006). Ovakav nalaz ukazuje na moguću infekciju riječnih galebova tijekom njihovoga brojnog okupljanja na odlagalištima otpada ili sličnim mjestima za hranjenje tijekom zime. Iako je samo jedna od 142 ptice bila pozitivna na protutijela za H5 podtip, nalaz se ne smije zanemariti znajući da naizgled zdravi riječni galebovi mogu nositi virus jako patogene influence podtipa H5N1. Unatoč tome, rezultati našeg istraživanja pokazuju da riječni galebovi češće bivaju inficirani drugim podtipovima virusa influence ptica te stoga najvjerojatnije nisu primarni nosioci virusa influence podtipa H5. Sukladno našim spoznajama, ovo je prvi dokaz virusa influence podtipa H16 u Hrvatskoj.

As immune responses to live and inactivated vaccines might differ, temporal responses of broiler chickens to vaccination were examined on the basis of the abundance in the circulating blood of gene transcripts of IFN-α, IFN-γ and IL-2, critical cytokines for immune responses. Blood samples were collected 6, 12 and 24 hours, and 7 and 14 days following vaccination with either live or inactivated Newcastle disease virus, La Sota strain, at 14 days of age, and the abundance of transcripts for each cytokine was assayed by real-time RT-PCR. Physiological saline and vaccine emulsion without viral antigen were administered to control groups for live and inactivated vaccine groups, respectively. The abundance of IFN-γ transcripts was elevated during the early times following vaccination and had reached baseline by the seventh day but the abundance of IFN-α transcripts remained elevated. Transcripts for neither IFN gene were detected in the control birds. The abundance of transcripts for each IFN was not different between the two vaccinated groups at any time. Transcripts for IL-2 were detected only in spleens from chicken embryos that had been inoculated with the live virus. The results show that cells stimulated to produce IFN-α and IFN-γ enter the circulating blood but those stimulated to produce IL-2 do not, or in very low number, and the IFN responses to both vaccines are the same.

This study describes the introduction and spread of avian influenza A (H5N1) subtype in Croatia. Seventeen isolates were identified during the period from October 2005 to March 2006, all originating from wild birds. The full-length nucleotide sequence analysis of the hemagglutinin (HA) gene of seven representative isolates revealed that three distinct genetic strains involved in the outbreaks, implicating at least three independent introductions of the virus into Croatia during a relatively short period of time. All three genetic strains belonged to clade 2.2 (Qinghai-like viruses) and each strain displayed significant similarity to concurrent H5N1 viruses from other European countries. The dominant strain of the virus was present in all four affected areas and in all three bird species (mute swan, mallard, and black-headed gull), indicating cross- species transmission of the virus. Two other genetic strains were found, together with the dominant strain, only in a marsh at the Adriatic coast during late February and early March 2006, which could be associated with frozen water surfaces in the continental part of Croatia as well as in Eastern Europe in early 2006 and the movement of birds toward warmer areas. This is also the first isolation of highly pathogenic avian influenza virus of H5N1 subtype from apparently healthy black-headed gulls.

Tijekom istraživanja ptica 2004. godine na zagrebačkom smetlištu Jakuševec zabilježio sam gniježđenje sivkaste bjeloguze Oenanthe oenanthe. To je najsjevernije za bilježeno gniježđenje ove vrste u Hrvatskoj. Najbliže redovito gnjezdilište sivkaste bje loguze u Hrvatskoj nalazi se u Gorskoj Hrvatskoj, približno 150 km jugozapadno od Zagreba.

Lesser Black-backed Gulls Larus fuscus were studied at Zagreb city rubbish dump, Jakuševec, from February 2000 to December 2003. In the year 2000 there were only 22 field days distributed over the whole year, but in 2001–2003 birds were counted regularly once a week. A total of 163 field days yielded 46 occasions on which Lesser Black-backed Gulls were observed. Most of the sightings were during spring migration, from March to May. The greatest number of Lesser Black-backed Gull recorded on Jakuševec rubbish dump was 51 on 12th April 2003. Results of this study show Lesser Black-backed Gull to be a regular visitor in Zagreb during the spring migration and irregular wintering species. The species was not recorded during the autumn migration at all., Od veljače 2000. do prosinca 2003. proučavao sam pojavljivanje tamnoleđeg galeba Larus fuscus na zagrebačkom odlagalištu otpada Jakuševec. U navedenom periodu, s iznimkom 2000. godine, na teren sam izlazio jedanput tjedno i brojao sve vrste galebova. Napravio sam 163 terenska izlaska, od kojih sam tamnoleđeg galeba zabilježio 46 puta. Tamnoleđeg galeba sam redovito promatrao u periodu od ožujka do svibnja. To je razdoblje njihove proljetne selidbe te su tada najbrojniji. Najveću brojnost zabilježio sam 12. travnja 2003 – 51 pticu, što je i najveća brojnost ikad zabilježena u Hrvatskoj. Većina ptica zabilježenih za proljetne seobe pripadaju podvrsti fuscus. Za vrijeme jesenske selidbe (kolovoz i rujan) tamnoleđeg galeba nisam zabilježio na području istraživanja. Na zagrebačkom području tamnoleđi galeb je neredovita zimovalica. U zimama 2000/01. i 2002/03. barem su dvije ptice zimovale. Uzevši u obzir da se u tom razdoblju na zagrebačkom odlagalištu otpada hranilo približno 10.000 galebova, moguće je da su neke ptice ostale neprimijećene i da je zimujuća populacija tih godina bila veća. Prije ovog istraživanja smatralo se da je tamnoleđi galeb u unutrašnjosti Hrvatske neredovita skitalica. Međutim, rezultati ovog istraživanja pokazuju da je tamnoleđi galeb u sjeverozapadnoj Hrvatskoj redovita, ali malobrojna preletnica i neredovita zimovalica.