Climate warming induced a stretch of the breeding season and an increase of second clutches in a passerine breeding at its altitudinal limits

The increase in the average air temperature due to global warming has produced an early onset of the reproduction in many migratory birds of the Paleartic region. According to the ‘mismatch hypothesis’ this response can lead to a decrease in the breeding output when the conditions that trigger the departure from the wintering areas do not match the availability of food resources in the breeding ground. We used 653 brooding events registered during the period 1991-2013 to investigate the link between climatic variables and individual breeding performance of a partially migratory passerine, the Rock Sparrow Petronia petronia, breeding at the altitude limit of its distribution. The laying date of the earliest first clutch was associated with local spring (minimum) temperatures but did not show a significant trend during the period considered. The laying date of the latest first clutch had a positive and statistically significant trend, unrelated to local covariates and resulting in a longer breeding season (∼1.5 day per year). A longer breeding season allowed birds to produce more second clutches, which proportion increased from 0.14 to 0.25. The average breeding success was also positively correlated with the average temperature in July and with the duration of the breeding season. Contrary to expectations, the most important climate-dependent effect was a stretch of the breeding season due to a significant increase of the laying date of the latest first-clutches rather than an earlier breeding onset. We show how climate changes act on bird populations through multiple paths and stress the need to assess the link between climatic variables and several aspects of the breeding cycle.

Mate Choice in Double-Breeding Female Great Tits (Parus Major): Good Males or Compatible Males

Producing two broods within the same season may be a good strategy by which short-lived species can maximize reproductive success. To produce two clutches in the same breeding season and to ensure offspring quality, choosing a good mate is important for females. Previous studies on double breeding focused on the associated influencing factors, and few studies examined how females choose social mates. Good genes and genetic compatibility are the two main hypotheses of the genetic benefit that females obtain from choosing mates. Uncovering the method used in mate choice for genetic benefits adopted by double-breeding females would provide a better understanding of the life history and rules of female choice. The great tit is an optionally double-breeding species in temperate-latitude populations. Here, we used a dataset for a Chinese population monitored between 2014 and 2016 to test two hypotheses on double-breeding female mate choice. A total of 30.1% of the breeding pairs initiated second breeding attempts, always remating with the same mate. The date of the first egg of the first brood did not affect initiation of a second brood, and female individual heterozygosity slightly influenced initiation of a second breeding. Female great tits choose males with both compatible genes and good genes in double-breeding mating. Double-breeding females prefer males with large breast stripes, high heterozygosity, and lower relatedness, while tarsus length, repertoire size, and individual F are not the main factors considered by females when selecting males for double breeding. The number of offspring of the first clutch did not affect the pairing status of male great tits in double breeding. The genetic quality of offspring from double-breeding pairs was higher than that of those from single-breeding pairs (higher heterozygosity and lower individual F). Taken together, our results showed that double breeding female great tits adopt multiple methods for genetic benefits to choose mates.

Behaviour and breeding peculiarities of the Snowy Sheathbill (Chionis alba Gmelin, 1789) in the water area of the Argentine Islands archipelago and adjacent territories (Graham Land, Antarctic Peninsula)

Systematic studies of the ornithofauna of the Argentine Islands archipelago by Ukrainian polar explorers began in the second half of the 90s. At the beginning of the XXI-st century, the southernmost breeding site of the Snowy Sheathbill (Chionis alba), Petermann Island, was discovered by Ukrainian ornithologists; later, nesting within the Argentine Islands archipelago was recorded. Breeding and behavioural peculiarities of the Snowy Sheathbill were studied during the XX-th (April 2015 - March 2016) and the XXIII-rd (April 2018 – March 2019) Ukrainian Antarctic expeditions, in accordance with the objectives of the State Target Scientific and Technical Research Program of Ukraine in Antarctica for 2010-2020. The distribution, abundance and detection of the Snowy Sheathbill nesting sites were investigated according to generally accepted methods, by means of surveys on permanent routes, and also by the method of point counting at Cape Marina Point on Galindez Island. During the reporting period, more than 400 hours were spent on conducting morning surveys and recording. The Snowy Sheathbill nests were examined on Galindez and Petermann Islands, the sites of probable breeding were investigated on Uruguay Island and Cape Tuxen (Antarctic Peninsula). In the spring of 2015, at Cape Marina Point on Galindez Island, breeding of one pair of the Snowy Sheathbill was recorded, and in the spring of 2018 – breeding of two pairs. In the spring of 2018, clutches on Galindez Island were registered: in the first clutch - three eggs, in the other – four ones. The average egg weight was 41.0 ± 0.8 (standard deviation – 1.9 g). Under favourable nesting conditions, the hatching of the first chicks is possible in late December. The average weight of newly hatched chicks was 33.3 ± 3.6 g. From January 19 to February 28, 2018, three chicks were weighed: the average increase in the weight of the first chick was 17.9 ± 1.3 g (standard deviation 7.6 g); the increase in the weight of the second one was 17.4 ± 1.3 g (standard deviation 7.7 g); the average increase in the weight of the third chick was smaller than in previous ones and amounted to 13.8 ± 1.5 g. The days without increase in weight were recorded: for the first chick such days were on February 19, 25, 28, for the second one only two days – on February 24 and 28; for the third chick - five days (on February 4, 13, 15, 27, 28). On the 41st day, the weight of the first chick was 680 g, the second one weighed 670 g, and the weight of the third chick was about 480 g. on the 40th day.

Artificial selection on male size depletes genetic variance but not covariance of life history traits in the yellow dung fly

SUMMARYThe evolutionary potential of organisms depends on the presence of sufficient genetic variation for traits subject to selection, as well as on the genetic covariances among them. While genetic variation ultimately derives from mutation, theory predicts the depletion of genetic (co)variation under consistent directional or stabilizing selection in natural populations. We estimated and compared additive genetic (co)variances for several standard life history traits, including some for which this has never been assessed, before and after 24 generations of artificial selection on male size in the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) using a series of standard half-sib breeding experiments. As predicted, genetic variances (VA), heritabilities (h2) and evolvabilities (IA) of body size, development time, first clutch size, and female age at first clutch were lower after selection. As independent selection lines were crossed prior to testing, we can rule out that this reduction is due to genetic drift. In contrast to the variances, and against expectation, the additive genetic correlations between the sexes for development time and body size remained strong and positive (rA = 0.8–0.9), while the genetic correlation between these traits within the sexes tended to strengthen (but not significantly so). Our study documents that the effect of selection on genetic variance is predictable, whereas that on genetic correlations is not.

Breeding biology of the Helmeted Manakin Antilophia galeata in an ecotone between the Atlantic Forest and the Cerrado

Manakins (Pipridae) are well-known by their promiscuous mating system. Nonetheless, scarce evidence suggests that the Helmeted Manakin Antilophia galeata, the only dichromatic manakin widely distributed in the South American Cerrado, is monogamic. We studied the breeding biology of the Helmeted Manakin in the state of Minas Gerais, southeastern Brazil. We found 17 nests, which are built in the forest undergrowth (usually below 3 m height). Nests are a cup attached by its top lip usually in the angle of a forked branch. The nest attachment zone is made mostly of spider silk. The structural zone is constructed with dry broad leaves, leaf petioles and horsehair fungus, which were bind together by a considerable amount of spider silk. The outer (decorative) zone is made with some hanging dry broad leaves, frequently forming a tail. Clutch size is always two (n = 12), and eggs are long oval, with a ground color in different shades of beige, marked with irregular spot, blotches and, sometimes, streaks ranging from light to dark brown. Mean eggs measurements were 23.9 x 16.3 mm (n = 14), weighting 3.3 g (n = 10). Eggs are laid once each day and hatching is synchronous. Females are the sole responsible for nest building (which usually took 10 days), incubation (18.5 days), and nestling care (18.3 days). The simple percentage of successful nests (n = 11) was 27% and predation was the main cause of nest failure. The breeding season extends from the second half of August to the first half of January. Renesting after loss of a first clutch is a common strategy and we recorded up to three nesting attempts for a single female. We present evidence that the Helmeted Manakin is promiscuous, as usual for a dichromatic manakin.

Breeding biology of the house sparrow (Passer domesticus) in the Faroe Islands / Nøringin hjá føroyska gráspurvinum (Passer domesticus)

<p><strong>A</strong><strong>bstract</strong>: The breeding biology of the Faroese house sparrow (<em>Passer domesticus</em>) is described based on the results from nestlings that were ringed just before they were fledging. By means of dates and numbers, the beginning and duration of the breeding seasons are determined and the reproductive output is estimated. Our study has shown that Faroese house sparrows produce two, occasionally three, broods annually. Overall, eggs of the first, second and third clutch are normally laid in the beginning of May, in the middle of June and in the beginning of July, respectively. In a season, a female produced 6.3 nestlings, on average. For the whole period, the average brood size was 3.5 nestlings. During the first part of the time series (1985­1989), the breeding season became earlier each year, but then to be later again in the years 1990 to 1992. The first clutch was laid more than five weeks earlier in 1989 than in 1985 and the second clutch almost seven weeks earlier.</p><p> </p><p><strong>Úrtak</strong>: Árini frá 1985 til 1992 vóru tilsamans 347 gráspurvaungar (<em>Passer domesticus</em>) merktir í bygdini Nólsoy, beint áðrenn teir vóru floygdir. Við at nýta dagfestingina tá ungarnir vórðu merktir og talið av ungum er ásett, nær og hvussu ofta gráspurvurin verpur og hvussu nógvar ungar hann fær hvørja ferð. Kanningarnar vísa, at føroyski gráspurvurin verpur tvær ferðir um árið, viðhvørt tó tríggjar ferðir: Fyrstu urptin er í byrjanini av mai mánað, tann næsta er um miðjan juni og triðja urptin í byrjanini av juli mánað. Hvør bøga fær í miðal 6,3 ungar um árið. Í miðal vóru 3,5 ungar í hvørjari urpt. Úrslit okkara vísa, at tey fyrstu árini varp gráspurvurin fyrr og fyrr, fyri hvørt árið. Hetta broyttist tó tey seinru árini sum kanningin vardi: Í 1989 vórðu fyrstu eggini vorpin meira enn fimm vikur fyrri enn í 1985, og næstu urptin næstan sjey vikur fyrr.</p>

The Chronic Effects of Salinity in the Biology of ?? Rotifers Brachionus calyciflorus Pallas

The present study included the effect of chronic exposure for two concentrations of NaC? salt on the biology of fresh water zooplankton species Brachionus calyciflorus (from ^otifera). The concentrations 0.5 , 0.75%o were used for chronic exposure to investigate its effects on the life tables, range of the rate of expectation for further life and reproduction. The rotifer B. calyciflorus was sensitive to salinity and may tried to protect the species by increasing the size (2.22 ind./clutch lor control group and 2.9? for 0.5%o concentration) and number of clutches produced ?.1? clutch/female for control group and 2.9 ' ' ' for 0.75 %0 concentration) beside stimulation the animal to produce the first clutch of eggs earlier? ? small reduction in mean longevity of the animal was noticed (8.1 day for control grou^ and7. ? day for 0.75 %0 concentration) while there was no effect on its average length and daily increasing during its life span

Physiological cost of maternal care? Effect of pre- and post-hatching care on the clutch size in the earwig Anisolabis maritima

There may be a trade-off between parental care and future reproductive success. Parental care usually consists of multiple components, and quantifying the cost of each component is necessary to assess the exact costs of parental care. In this study, I examined the trade-offs associated with maternal care in the earwig Anisolabis maritima (Dermaptera: Anisolabididae). I evaluated how many clutches A. maritima can produce and how the number and size of the clutch are affected by maternal care, distinguishing the cost of each component. The interval from the time point at which the mothers were removed from their eggs or young to produce the next clutch differed with treatment, and a significant interaction was observed between the effects of clutch order and presence of care on the size of the next clutch when the first clutch was removed immediately. However, longevity and total lifetime fecundity were not different in the presence or absence of care. This showed that females which were removed from a clutch produced the second or later clutches more rapidly although the clutch sizes were smaller. Because the total lifetime fecundity did not differ, irrespective of the presence or absence of care, it is possible that the costs of such care in A. maritima have a small effect.

Substitute nesting by Imperial Eagles (Aquila heliaca) in Slovakia

During consistent monitoring of nesting pairs of Imperial Eagles primarily in Eastern Slovakia it was found that if for some reason the first clutch of eggs was destroyed at the very beginning of nesting, i.e. in late March or the first half of April, the eagles proceeded with substitute nesting. They built a replacement nest, so far always in a different place, in which a new clutch was laid. If the nesting was successful, then as a rule they raised one, and in two cases two offspring.