Complete Genome Sequence, Molecular Characterization and Phylogenetic Relationships of a Novel Tern Atadenovirus

Discovery and study of viruses carried by migratory birds are tasks of high importance due to the host’s ability to spread infectious diseases over significant distances. With this paper, we present and characterize the first complete genome sequence of atadenovirus from a tern bird (common tern, Sterna hirundo) preliminarily named tern atadenovirus 1 (TeAdV-1). TeAdV-1 genome is a linear double-stranded DNA molecule, 31,334 base pairs which contain 30 methionine-initiated open reading frames with gene structure typical for Atadenovirus genus, and the shortest known inverted terminal repeats (ITRs) within the Atadenovirus genus consisted of 25 bases. The nucleotide composition of the genome is characterized by a low G + C content (33.86%), which is the most AT-rich genome of known avian adenoviruses within Atadenovirus genus. The nucleotide sequence of the TeAdV-1 genome shows high divergence compared to known representatives of the Atadenovirus genus with the highest similarity to the duck atadenovirus 1 (53.7%). Phylogenetic analysis of the protein sequences of core genes confirms the taxonomic affiliation of the new representative to the genus Atadenovirus with the degree of divergence from the known representatives exceeding the interspecies distance within the genus. Thereby we proposed a novel TeAdV-1 to be considered as a separate species.

Highly Conservative Pattern of Sex Chromosome Synapsis and Recombination in Neognathae Birds

We analyzed the synapsis and recombination between Z and W chromosomes in the oocytes of nine neognath species: domestic chicken Gallus gallus domesticus, grey goose Anser anser, black tern Chlidonias niger, common tern Sterna hirundo, pale martin Riparia diluta, barn swallow Hirundo rustica, European pied flycatcher Ficedula hypoleuca, great tit Parus major and white wagtail Motacilla alba using immunolocalization of SYCP3, the main protein of the lateral elements of the synaptonemal complex, and MLH1, the mismatch repair protein marking mature recombination nodules. In all species examined, homologous synapsis occurs in a short region of variable size at the ends of Z and W chromosomes, where a single recombination nodule is located. The remaining parts of the sex chromosomes undergo synaptic adjustment and synapse non-homologously. In 25% of ZW bivalents of white wagtail, synapsis and recombination also occur at the secondary pairing region, which probably resulted from autosome−sex chromosome translocation. Using FISH with a paint probe specific to the germline-restricted chromosome (GRC) of the pale martin on the oocytes of the pale martin, barn swallow and great tit, we showed that both maternally inherited songbird chromosomes (GRC and W) share common sequences.

The quantitative genetics of fitness in a wild bird population

Additive genetic variance in fitness equals the change in mean fitness due to selection. It is a prerequisite for adaptation, as a trait must be genetically correlated with fitness in order to evolve. Despite its relevance, additive genetic variance in fitness has not often been estimated in wild populations. Here, we investigate additive genetic variance in lifetime fitness, as well as its underlying components, in common terns (Sterna hirundo). Using a series of animal models applied to 28 years of data comprising ca. 6000 pedigreed individuals, we find nominally zero additive genetic variance in the Zero-inflated component of lifetime fitness, and low but unreliable variance in the Poisson component. We also find low but likely nonzero additive genetic variance in adult annual reproductive success, but not in survival. As such, our study (i) suggests heritable variance in common tern fitness to result mostly from heritable variance in reproductive success, rather than in early-life or adult survival, (ii) shows how studying the genetic architecture of fitness in natural populations remains challenging, and (iii) highlights the importance of maintaining long-term individual-based studies such that a major research aim in evolutionary ecology will come within better reach in the next decade.

Some Population Aspects of Common Tern Sterna hirundo Breeding in Algeria at a Small Mediterranean Island (East Coast of Algeria)

We present the first detailed study of population dynamics, breeding biology and egg measurement of Common Terns. During six years (from 2004 to 2009) of monitoring, from mid-May to mid-August, 74 Common Terns individual were recorded at Laouinet small island, El Tarf, northeast of Algeria, witha finite population growth rate that indicated an alarming population decline(λ = -0.62: Lambda). Sterna hirundo build its nests (n = 37) in the northeast at a mean distance of 7.58 m from the closest edge of rocks. The nests were closed and ovoid, constituted mainly of mussel shells Sandpit, stems and leaves. Incubation was performed by pairs of common tern and lasted 25.5 ±3.4 days. We recorded a clutch size of 1 to 3 eggs with mean clutch size of 2.45±0.65 (41.24±0.83 × 30.46±0.62 mm). The egg parameters (volume, mass, shape index) varied between the six years of the study. The egg volume (19.24±0.87) depended more on egg width (30.46±0.62), however the egg shape (0.73±0.20) depended negatively on the egg length (41.24±0.83) but not on the egg width. Our results also showed a stabilized hatching success and a best estimation of breeding success. The hatching success did not vary between years: 70.5% in 2004, 68.75% in 2005, 71.42% in 2006, 71.42% in 2007, 69.23% in 2008 and 69.23% in 2009.

Draft Genome Sequences of Vibrio cholerae Non-O1, Non-O139 Isolates from Common Tern Chicks (Sterna hirundo) following a Mass Mortality Event

ABSTRACT Vibrio cholerae is an inhabitant of aquatic environments worldwide. Here, we report the draft genome sequences of eight V. cholera non-O1, non-O139 isolates that were recovered from the corpses of two seabird chicks (common terns) following a mass mortality event in a German breeding colony in 2019.

Using Thermal Infrared Cameras to Detect Avian Chicks at Various Distances and Vegetative Coverages

Population monitoring of nesting waterbirds often involves frequent entries into the colony, but alternative methods such as local remotely sensed thermal imaging may help reduce disturbance while providing a cost-effective way to survey breeding populations. Such an approach can have high initial costs, however, which may have reduced the number of studies investigating functionality of paired thermal infrared camera and small unmanned aerial systems. Here, we take the first step of exploring the ability of two thermal infrared cameras to detect an avian chick under varying vegetative cover and distances, preceding field-mounting applications on a small unmanned aerial system. We created seven “bioboxes” to simulate a range of natural vegetation types and densities for a globally important colonial ground-nesting waterbird species, the common tern Sterna hirundo. We placed a juvenile chicken Gallus gallus (surrogate for the locally endangered common tern) in each box, and we tested two market-accessible infrared cameras (produced by FLIR Systems and Infrared Cameras, Inc.) at five elevations using a stationary boom (maximum height = 12 m). We applied computer-based digital thresholding to collected images, identifying pixels meeting one of seven threshold values. The chick was visible from at least one threshold value in 19 and 31 of 35 processed by the FLIR Systems and Infrared Cameras, respectively. Percentage of the chick identified across thresholds was generally highest at lower threshold values and elevations and decreased as elevation and threshold increased; however, the relative importance of each variable changed dramatically across bioboxes and camera types. Ability to detect a chick from processed images generally decreased with increasing elevation, and although we made no quantitative comparisons among boxes, detectability appeared greatest in images from both cameras when little or no vegetation was present. Interestingly, no single threshold value was best for all bioboxes. We observed notable differences between cameras including visual resolution of detected temperature differentials and image processing speed. Results of this controlled study show promise for the use of thermal infrared systems for detecting cryptic species in vegetation. Future research should work to combine thermal infrared and visual sensors with small unmanned aerial systems to test applicability in a mobile field application.

Food source as a factor determining birds' exposure to hazardous organic pollutants and egg contamination

Alimentary exposure is the main factor determining halogenated organic compound pollution of wildlife, with birds’ eggs recognised as bioindicators of these contaminants and often used as a non-invasive monitoring tool. Comparisons of bird species from two aquatic environments, namely a marine coastal area (Gdansk Bay) and an inland reservoir (Włocławek Dam on the Vistula River), indicated significant differences in egg contamination. Herring gull eggs from Włocławek Dam had high concentrations of highly chlorinated dioxin (i.e. octachlorodibenzodioxin, which accounted for 37% of all polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans, PCDD/Fs). In contrast, eggs from terns feeding along the coastal area of the Southern Baltic contained high concentrations of lowly chlorinated furans (i.e. pentachlorodibezofuran, which accounted for 46 and 45% of all PCDD/Fs in eggs from the sandwich tern and common tern respectively). The congener patterns in terns’ eggs were similar to those reported previously for Baltic fish. Polychlorinated biphenyl congener 180 had the highest concentrations among the mono-ortho chlorinated biphenyls, whereas concentrations of non-dioxin-like chlorinated biphenyls were 10-fold higher than those of the other congeners analysed, but the congener pattern in eggs from both species (sandwich and common tern) was similar to that reported in other studies. Among the hexabromocyclododecane (HBCD) isomers, α-HBCD dominated in all eggs analysed (accounting for >97% of all HBCDs). The total HBCD concentration in gulls’ eggs from the inland reservoir was approximately half that in eggs from the common and sandwich terns (mean±s.d. 47.33±33.22v. 97.98±59.69 and 104.00±63.66ngg–1 lipid weight respectively).