Onset Of Incubation Research Articles

Breeding ecology of the Quailfinch (Ortygospiza atricollis) in the Limpopo Province, South Africa

The Quailfinch (Ortygospiza atricollis) is a widespread African estrildid that features in specialist avicultural collections. However, the species is poorly known and has proven difficult to maintain in captivity, and as such, most captive stock represent wild-caught specimens. Here we report on the breeding ecology of a population of wild Quailfinches as observed at 62 nests in the 2012–2013 and 2013–2014 breeding seasons. Although Quailfinch bred during the wet season, incidental observations suggest rainfall patterns and the availability of suitable habitat for nesting, specifically habitat structure, may influence the onset of the breeding season at a local scale. Both sexes participated in all aspects of nest construction, including collection of material, construction, and maintenance. Nests were occupied for extensive periods prior to the commencement of laying, fulfilling a possible nest guarding or pair bonding function. Mean clutch size was 4.8 eggs (SD 0.2) and there were no significant seasonal differences in clutch size. Both sexes incubated and the incubation period lasted 14 d (SD 0.8). In common with many other estrildid species, there was considerable variation in the onset of incubation. Mean nest attendance during incubation was 83% and was similar between the sexes. The mean nestling period lasted 16.8 d (SD 0.8) and both sexes brooded and provisioned the nestlings with seeds and occasionally invertebrates. Growth was unusually rapid for estrildids, but within the range expected for ground-nesting passerines. The overall breeding success was 12% with predation being the main cause of nest failure.

Nest microclimate and limits to egg viability explain avian life-history variation across latitudinal gradients.

Variation in life-history strategies is central to our understanding of population dynamics and how organisms adapt to their environments. Yet we lack consensus regarding the ecological processes that drive variation in traits related to reproduction and survival. For example, we still do not understand the cause of two widespread inter- and intraspecific patterns: (1) the ubiquitous positive association between avian clutch size and latitude; and (2) variation in the extent of asynchronous hatching of eggs within a single clutch. Well-known hypotheses to explain each pattern have largely focused on biotic processes related to food availability and predation risk. However, local adaptation to maintain egg viability could explain both patterns with a single abiotic mechanism. The egg viability hypothesis was initially proposed to explain the cause of asynchronous hatching and suggests that asynchronous hatching results from early incubation onset in response to unfavorable nest microclimatic conditions, which otherwise reduce egg viability. However, allocation of resources to early incubation, prior to clutch completion, may energetically constrain clutch size and help explain the positive association between clutch size and latitude. We measured intraspecific variation in five functionally linked life-history traits of burrowing owls at five study sites spanning a 1,400-km latitudinal transect in western North America: clutch size, the timing of incubation onset, the degree of hatching asynchrony, the probability of hatching failure, and nestling survival. We found that most traits varied clinally with latitude, but all the traits were more strongly associated with individual nest microclimates than with latitude, and all varied with nest microclimate in the directions predicted by the egg viability hypothesis. Furthermore, incubation began earlier, hatching asynchrony increased, and clutch size declined across the breeding season. These results suggest that nest microclimate drives an important life-history trade-off and that thermal gradients are often sufficient to account for observed biogeographic and seasonal patterns in life-history strategies. Furthermore, our results reveal a potentially important indirect mechanism by which reproductive success and recruitment could be affected by climate change.

Impacts of ambient temperature and clutch size on incubation behaviour onset in a female‐only incubator songbird

Ambient temperature is assumed to be the major cue used by passerines to synchronize their laying and hatching dates to the expected peak of prey availability. While laying eggs, females are still able to fine‐tune their hatching date following increasing or decreasing patterns of ambient temperature, mostly via changes in incubation onset. The onset of incubation behaviour in relation to the laying sequence could have later consequences for the duration of the incubation period and the extent of hatching asynchrony. Clutch size is also known to affect incubation patterns and might therefore condition potential responses to changing temperatures. In this study we assessed the association of ambient temperature and clutch size with the onset of four different incubation behaviours: partial and full nocturnal incubation, and partial and full diurnal incubation. We also evaluated how the onset and duration of each incubation behaviour might predict the duration of diurnal full incubation and the extent of hatching asynchrony. To achieve our aims, we monitored incubation behaviour using temperature data loggers during the egg‐laying period in three Mediterranean Great Tit Parus major populations in three consecutive years. Our results showed that increasing temperatures were related to an advance of diurnal partial incubation, but not its duration or the onset of full incubation behaviour. We did not find any effect of ambient temperatures on nocturnal incubation. However, females lengthened nocturnal partial incubation and delayed the onset of nocturnal full and diurnal partial incubation when laying larger clutches. Longer diurnal incubation before clutch completion was associated with greater hatching asynchrony. Moreover, longer diurnal partial incubation shortened the duration of the full incubation period. In conclusion, increasing ambient temperatures during the egg‐laying period advanced diurnal partial incubation, indirectly shortening the full incubation period and increasing hatching asynchrony.

Trends in Black Swift (Cypseloides niger) breeding phenology, productivity, and nest success in southwest Colorado, 1996–2017

This study presents breeding phenology, fledgling production, and nest success for the Black Swift (Cypseloides niger) over a 22 year period at the Box Canyon colony, Ouray, Colorado, USA. Data were collected annually from 1996 to 2017 by direct observation from arrival of the birds at the nesting colony until all adults and fledglings departed. We documented dates of first arrival, laying, incubation onset, hatching, and fledging, and determined the intervals from arrival to laying, laying to incubation, length of incubation, and length of the nestling period in each year. Breeding events followed each other closely and showed little chronological change throughout the study. We identified a negative trend in the number of nest attempts and fledged Black Swift chicks over time but found no relationship between these 2 trends and the environmental factors of summer temperature, summer precipitation, or tourist visitation. The Mayfield estimate of nest success for all nest attempts was 77.5%. There was unexplained annual variation in nest success, but the trend in nest success remained static, with no correlation between nest success and temperature, precipitation, or tourist visitation. This study represents the largest dataset and longest-duration investigation into the breeding phenology and nest success of the Black Swift.

Determination of in vitro rumen digestibility and potential feed value of tiger nut varieties

Tiger nut (Cyperus esculentus L.), or chufa, is a plant that is found in nature and is cultivated for its edible tubers. The purpose of this study was to determine the chemical composition, nutritive value, and in vitro digestibility of three tiger nut varieties using the in vitro gas production technique. These varieties were Sarışeker (yellow), Introduction 1, and Balyumru (brown). Rumen fluid was obtained from two cannulated Holstein animals. Time-dependent in vitro gas production was monitored at 3, 6, 9, 12, 24, 48, 72, and 96 hours of incubation. The varieties differed in dry matter (DM), crude ash (CA), ether extract (EE), neutral detergent fibre (NDF), and non-fibre carbohydrate (NFC) content (P <0.05). They also differed in the instantaneous volume of gas produced and in time-dependent gas production. Balyumru produced more gas at the onset of incubation than Introduction 1 and Sarışeker. However, over time, the gas produced by digestion of Introduction 1 exceeded the other two varieties. The amounts of gas produced at each time-point were intercorrelated. It is recommended that these results should lead to further evaluation in in vivo studies.
 Keywords: chemical composition, energy content, in vitro gas production

Partial Incubation and Hatching Asynchrony in the Red-Shouldered Hawk (Buteo lineatus)1

Like many raptors, Red-shouldered Hawks (Buteo lineatus) exhibit asynchronous hatching, which is thought to be a parental strategy for rearing the maximum number of offspring under conditions of unpredictable prey availability. Current knowledge of incubation patterns and the associated behavioral mechanisms by which asynchronous hatching occurs in raptors is limited, and few detailed quantitative studies are available for any species of Accipitriformes. We investigated the effects of egg-laying intervals and parental behavioral incubation patterns during egg-laying on hatching asynchrony in the Red-shouldered Hawk. We used 24-hr/d digital color/infrared video cameras at 15 Red-shouldered Hawk nests to record egg-laying and hatching, and to quantify the proportion of time parents spent incubating, standing, or absent from the nest. The mean egg-laying interval was 2.9 ± 0.1 d or 69.8 ± 2.2 hr (range = 65.8–74.2 hr), and the mean duration of incubation (from the onset of full incubation to hatch) for last-laid eggs was 33 d (32–34 d, n = 15). Red-shouldered Hawks exhibited partial incubation behavior, with the delay in the onset of full incubation varying by clutch size and among individuals; full incubation generally began with or just after the laying of the penultimate egg of the clutch. The mean interval between the hatching of the first and second egg was 0.56 ± 0.49 d; between the second and third eggs, 1.24 ± 0.71 d (P= 0.0215); and between the third and fourth eggs, 2.42 ± 0.38 d (P < 0.0004). The total amount of time parents at each nest spent incubating during the egg-laying period explained most of the variation in the amount of time between the hatching of their first and last egg (the hatching span; r2 = 0.83, P < 0.0001). Hatching patterns were the result of both the egg-laying intervals and the pattern of partial incubation, which may represent an adaptive mechanism to reduce the hatching interval while maintaining the hatching asynchrony.

Changes of nest mass in relation to nesting stages in the Great Tit Parus major

ABSTRACT Capsule Nest mass of the Great Tit Parus major increases over the course of the nesting cycle and the magnitude of the increase between incubation and post-fledging stage is positively correlated with brood size. Aims To investigate whether, in the Great Tit, fresh nest mass changes over the course of the nesting cycle, is correlated with dry nest mass assessed after the nestlings have fledged, and whether temporal variation in fresh nest mass is associated with clutch or brood size. Methods Fresh nest mass was measured at the beginning of egg laying, the beginning of incubation and shortly after the nestlings fledged. Dry nest mass was measured after subjecting nests collected at the end of the nesting cycle to a drying procedure. Results Between the onset of egg laying and early incubation nest mass increased by 14.1%, and between early incubation and post-fledging stage by 69.7%. The magnitude of the increase over the late nesting stage correlated positively with the number of 14 day-old nestlings. Nest dry mass and post-fledging fresh nest mass, but not mass at the early stages of the nesting cycle (egg laying and incubation), were positively correlated with clutch and brood sizes. There was no variation among the nests in the pattern of mass change between the egg laying and incubation stages, while this pattern varied widely between the incubation and post-fledging stages. Conclusions While nests are most commonly weighed after the nestlings have fledged, we suggest that in order to obtain the most reliable estimate of investment in nest building, nests should be weighed during the early stages of the nesting cycle, preferably at the onset of incubation, to avoid brood size-dependent changes in their masses.

OBSERVATIONS ON THE PARENTAL CARE BEHAVIOR OF THE MAROON-CHESTED GROUND DOVE (PARACLARAVIS MONDETOURA) IN SOUTHEASTERN ECUADOR

We present the first observations of parental care behaviors of the Maroon-chested Ground-Dove (Claravis mondetoura) using 222.5 hours of recorded observations from a single nest found in tropical montane forest in the Tapichalaca Biological Reserve in south-east Ecuador. Recording began with the onset of incubation and continued through fledging. Observations of male and female attendance at the nest were used to analyze visit frequency and timing, duration, and differences in male and female investment in the reproductive effort. Both adults spent time incubating, brooding, and shared feeding responsibilities and patterns observed reflected those commonly seen in other Neotropical Columbidae.

Surface temperatures of non-incubated eggs in great tits (Parus major) are strongly associated with ambient temperature.

Temperature is one of the best investigated environmental factors in ecological life-history studies and is increasingly considered in the contexts of climate change and urbanization. In avian ecology, few studies have examined the associations between thermal dynamics in the nest environment and its neighbouring air. Here, we placed avian nests and non-incubated eggs inside nest boxes at various air temperatures that ranged from 0.3 to 33.1 °C, both in the field and in laboratory conditions. We measured how the design of the boxes, their compass orientation and their location in more or less urbanized environments affected the surface temperature of nests and eggs. We also assessed whether covering the eggs with lining material influenced their surface temperature. Overall, across all performed tests, we found that the surface temperature of nests and eggs strongly reflected the air temperature measured outside of the nest boxes. While the design of the nest boxes had little influence on the temperature of nests and eggs, orienting the nest boxes to the north or to the west significantly decreased their surface temperature. The presence of lining material also kept eggs slightly warmer when air temperatures were low. Altogether these results suggest that non-incubated eggs are not well protected against extreme air temperatures prior to the onset of incubation. From an evolutionary point of view, producers of ectotherm eggs need therefore to time egg-laying appropriately in order to avoid unfavourable thermal nest environments.

Поиск оптимальных способов хранения яиц непарного шелкопряда Lymantria dispar (Linnaeus, 1758) для разведения на них яйцееда Оoencyrtus kuvanae (Howard, 1910)

В статье приводятся результаты поиска оптимальных способов хранения яиц непарного шелкопряда Lymantria dispar для разведения на них яйцееда Ooencyrtus kuvanae. Определены основные факторы, снижающие качество биоматериала яйцекладок. Установлены показатели выхода яйцеедов при разных способах хранения и обработки яиц из яйцекладок. The article is devoted to a detailed consideration of a number of questions about the storage of biological material, egg-laying’s gypsy moth – Lymantria dispar (Linnaeus, 1758), eggs from which, are subsequently, used for breeding parasitic wasp – Ooencyrtus kuvanae (Howard, 1910), and search among them optimal. The jurisdiction is a review of the knowledge of this problem in Russia and abroad [1]. In the main part of the article presents data conducted in 2018–2019 years, the first author, 15 series of experiments. The materials consider in detail the influence of abiotic and biotic factors on the quality of the eggs of the gypsy moth, needed later, for breeding parasitic wasp – Ooencyrtu skuvanae (How.). The work examines the quality of eggs collected the Tyumen region at different times: summer, autumn and spring, before the onset of incubation. The effect of cooling eggs to + 2...0 °С is studied, and freezing to -15...-17 °С. Also examines the impact of the duration of egg storage, freshly laid eggs are compared with stored up to 5 months and from 5 to 10 months. Studied the use of unfertilized eggs gypsy moth for growing parasitic wasp – Ooencyrtus kuvanae (How.). Additionally, an experiment was conducted to assess the effectiveness of the application of eggs processing with hot water up to + 60°С for 1 hour, to prevent exit of larvae in the process of infection parasitic wasp, especially long-term storage eggs or egg-laying’s collected in the spring with the already started incubation process. The material in the work is supported by graphic material: a tables and graphs. In conclusion, the authors of the work, on the basis of the data obtained, assess the significance of factors that have a negative impact on the quality of eggs, as well as offers recommendations on the best ways to store biomaterials, including the use of unfertilized eggs and the appropriateness of using heat treatment with hot water. At the end it is given a list of used literature, consisting of 11 sources. Referenсe 1. Methodological guidelines on the use of introduced parasitic wasp Ooencyrtus kuvanae against gypsy moth]. – Access mode : http://www.agrozoo.ru/base_gvc/karantin/document/17.html/ (date of application 25.07. 2019).

Cuckoos use host egg number to choose host nests for parasitism.

To maximize their offspring success common cuckoo (Cuculus canorus) females should lay their eggs into host nests before incubation has begun. This ensures that the parasite chick hatches before all host chicks and can evict its foster siblings to monopolize host parental care. Many studies have demonstrated that most cuckoo eggs are indeed laid before the onset of host incubation. But cues used by female cuckoos to choose the right nest at the right time remain unclear. Here, we combine field observations with a field experiment to test whether female cuckoos use the number of eggs in the nests of their Oriental reed warbler (Acrocephalus orientalis) hosts to direct their choice. Over 8 years of field observations and 5 years of experiments, cuckoo females placed the majority of their eggs in nests with fewer than three host eggs, i.e. early in the laying sequence. For natural nests, the cuckoos may use information gleaned from the activity and behaviour of the host parents to make their choice. In our sets of experimental nests containing different numbers of model eggs, the vast majority of parasitism events occurred in nests containing a single egg. To our knowledge, this is the first field experiment showing that cuckoos choose host nests for parasitism based on the number of host eggs they contain. It appears that cuckoo females use the egg number to estimate the appropriate host nest stage for timely parasitism.

Nest Desertion by Blackcaps Sylvia atricapilla in Response to Experimental Partial Clutch Reduction

If the number of eggs in a clutch is reduced by predators, birds have to decide whether to continue investing time and energy in this clutch or begin a new one. The aim of this study was to assess the desertion frequency of nests with an experimentally reduced number of eggs depending on the stage of incubation, degree of clutch reduction and advancement of the breeding season in the Blackcap Sylvia atricapilla. Only five-egg clutches, most typical for Blackcaps, were investigated. At the beginning of the incubation period (one day after the last egg was laid) or at the end of incubation (10 days after the last egg), two or three eggs were removed. On the next day the clutch was monitored for desertion/incubation. Blackcaps deserted clutches significantly more often when these were reduced by three eggs at the onset of incubation (56 out of 59 clutches) compared to clutches reduced at the end of incubation (33 out of 81 clutches). As the breeding season progressed there was a significant decrease in the proportion of nests that were deserted after a three-egg clutch reduction at the end of incubation. The advancement of the breeding season did not affect the desertion frequency when eggs were removed at the beginning of incubation. Blackcaps continued incubation of all clutches reduced by two eggs (n = 20), despite reduction occurring at the beginning of incubation and early in the breeding season. These results are consistent with predictions from life-history theory in general, and the brood value hypothesis in particular.

When are egg-rejection cues perceived? A test using thermochromic eggs in an avian brood parasite host.

At the core of recognition systems research are questions regarding how and when fitness-relevant decisions made. Studying egg-rejection behavior by hosts to reduce the costs of avian brood parasitism has become a productive model to assess cognitive algorithms underlying fitness-relevant decisions. Most of these studies focus on how cues and contexts affect hosts' behavioral responses to foreign eggs; however, the timing of when the cues are perceived for egg-rejection decisions is less understood. Here, we focused the responses of American robins Turdus migratorius to model eggs painted with a thermochromic paint. This technique modified an egg's color with predictably varying temperatures across incubation: at the onset of incubation, the thermochromic model egg was cold and perceptually similar to a static blue model egg (mimicking the robin's own blue-green egg color), but by the end of an incubation bout, it was warm and similar to a static beige egg (mimicking the ground color of the egg of the robin's brood parasite, the brown-headed cowbird Molothrus ater). Thermochromic eggs were rejected at statistically intermediate rates between those of the static blue (mostly accepted) and static beige (mostly rejected) model eggs. This implies that at the population level, egg-rejection relevant cues are not perceived solely when arriving to or solely when departing from the nest. We also found that robins rejected their own eggs more often when exposed to color-changing model eggs relative to static eggs, suggesting that recognizing variable foreign eggs entails costly rejection errors for this host species.

Parental investment asymmetries of a globally endangered scavenger: unravelling the role of gender, weather conditions and stage of the nesting cycle

ABSTRACTCapsule: In Egyptian Vultures Neophron percnopterus, both sexes invested similar parental effort throughout the breeding period. However, there was variation in the degree of intensity of parental care during some stages of the breeding period, suggesting that sex-role specialization exists for some activities.Aims: To quantify parental care behaviour of Egyptian Vultures for the first time and to examine the role of sex, weather conditions, and stage of nesting cycle on breeding ecology.Methods: We monitored 15 nests of Egyptian Vultures to analyse parental care investment. We collected data on nine different behavioural parameters/activities per sex, which were recorded throughout the entire breeding period. Variation in parental investment was analysed using generalized linear mixed models.Results: Females invested more effort in incubation/brooding (61.45% for females and 31.54% for males) and egg turning (0.45 events/h for females and 0.37 events/h for males) while males contributed more to nest material delivery to the nest (0.67 deliveries/h for males and 0.14 deliveries/h for females). Conversely, both sexes invested the same effort in nestling attendance (21.89% for females and 21.21% for males) and food provisioning (0.28 items/h for females and 0.25 items/h for males). Furthermore, parental investment was not affected by weather, especially during critical moments such as incubation/brooding, however, changeover rate was positively related to temperature.Conclusion: Our results suggest that, in the Egyptian Vulture, one sex is not entirely responsible for a particular task and the compensatory effort of the other mate is required. Finally, our findings indicate that major events such as incubation onset and hatching caused important shifts in the patterns of parental investment.

Experimentally induced increases in fecundity lead to greater nestling care in blue tits.

Models on the evolution of bi-parental care typically assume that maternal investment in offspring production is fixed and predict subsequent contributions to offspring care by the pair are stabilized by partial compensation. While experimental tests of this prediction are supportive, exceptions are commonplace. Using wild blue tits (Cyanistes caeruleus), we provide, to our knowledge, the first investigation into the effects of increasing maternal investment in offspring production for subsequent contributions to nestling provisioning by mothers and male partners. Females that were induced to lay two extra eggs provisioned nestlings 43% more frequently than controls, despite clutch size being made comparable between treatment groups at the onset of incubation. Further, experimental males did not significantly reduce provisioning rates as expected by partial compensation, and if anything contributed slightly (9%) more than controls. Finally, nestlings were significantly heavier in experimental nests compared with controls, suggesting that the 22% average increase in provisioning rates by experimental pairs was beneficial. Our results have potential implications for our understanding of provisioning rules, the maintenance of bi-parental care and the timescale over which current–future life-history trade-offs operate. We recommend greater consideration of female investment at the egg stage to more fully understand the evolutionary dynamics of bi-parental care.

Seasonal and diurnal patterns of population vocal activity in avian brood parasites

Patterns of vocal activity may involve information about vocalizations themselves as well as their function. In birds, vocal activity at the individual and population level is generally closely associated with breeding cycles, reaching the peak during territorial and mating competition, and decreasing with the onset of egg incubation and chick feeding. However, little is known about patterns of vocal activity in avian brood parasites that have unusual breeding cycles without parental care. Using passive acoustic monitoring, we determined the seasonal and diurnal patterns of population vocal activity in two avian brood parasites: the Common CuckooCuculus canorusand the Lesser CuckooC. poliocephalus. We found that both species and both sexes showed a similarly highly structured pattern of seasonal vocal activity, reaching a sharp peak in the early breeding season when birds compete for territories and mates, although males sang more frequently than females. Likewise, the diurnal patterns of vocal activity were similar in both species and both sexes of cuckoos, with peak activity occurring around dawn. Nocturnal calls by male cuckoos were also detected in both species, but only in the early breeding season. Collectively, the observed patterns of population vocal activity may suggest that the absence of parental care may not extend the period of vocal activity in these two species of brood parasites.

Seasonal and Diurnal Variation of Singing Activity: Their Possible Relationship with Intra- and Inter-Sexual Function in the Savannah Sparrow, Passerculus sandwichensis.

We studied seasonal and diurnal variation of singing activity in a single-song repertoire species, the savannah sparrow (Passerculus sandwichensis), to explore the possible functions of the song. We observed a total of 47 territorial males (11 over three years, 28 over two years) on a daily basis. For all paired and unpaired males, and across all stages of the breeding season, we recorded total number of songs produced (singing persistence), the number of instances of aggression per 10-minute period in each focal male, and the number of songs per 3-minute period (singing intensity). Male savannah sparrows showed different singing activity in different behavioural contexts: 1) unpaired males sang more persistently, but less intensely than paired males; 2) paired males markedly reduced their singing persistence, but showed higher singing intensity, especially in the evening; 3) singing intensity of paired males peaked during the egg-laying period. The different patterns of singing activity in relation to time of day, nuptial status, and female breeding stage suggest that though the birds each possess only a single song type, the differential activities may play important roles in intra- and inter-sexual communication systems: it is argued that 1) intense singing by paired males in the evening plays a role in territory defense, while persistent singing by unpaired males in the morning plays a role in mate attraction; 2) especially high evening singing activity during the egg-laying period may relate to changed female behavior at the nest associated with the onset of incubation.

Different incubation patterns affect selective antimicrobial properties of the egg interior: experimental evidence from eggs of precocial and altricial birds.

Avian eggs contend with omnipresent microorganisms entering the egg interior, where they affect embryo viability and hatchling phenotype. The incubation behaviour and deposition of egg white antimicrobial proteins (AMPs) vary highly across the avian altricial-precocial spectrum. Experimental evidence of how these alterations in avian reproductive strategies affect the antimicrobial properties of the precocial and altricial egg interior is lacking, however. Here, we tested the egg white antimicrobial activity in eggs of two representative model species, from each end of the avian altricial-precocial spectrum, against potentially pathogenic and beneficial probiotic microorganisms. Eggs were experimentally treated to mimic un-incubated eggs in the nest, partial incubation during the egg-laying period, the onset of full incubation and the increased deposition of two main egg white AMPs, lysozyme and ovotransferrin. We moreover assessed to what extent egg antimicrobial components, egg white pH and AMP concentrations varied as a result of different incubation patterns. Fully incubated precocial and altricial eggs decreased their antimicrobial activity against a potentially pathogenic microorganism, whereas partial incubation significantly enhanced the persistence of a beneficial probiotic microorganism in precocial eggs. These effects were most probably conditioned by temperature-dependent alterations in egg white pH and AMP concentrations. While lysozyme concentration and pH decreased in fully incubated precocial but not altricial eggs, egg white ovotransferrin increased along with the intensity of incubation in both precocial and altricial eggs. This study is the first to experimentally demonstrate that different incubation patterns may have selective antimicrobial potential mediated by species-specific effects on antimicrobial components in the egg white.

Gobbling activity of eastern wild turkeys relative to male movements and female nesting phenology in South Carolina

ABSTRACTWild turkeys (Meleagris gallopavo) use a polygynous mating system, and males must balance fitness benefits of courtship displays against costs of their reproductive strategies. Wild turkeys are the only gamebird species in the contiguous United States hunted primarily during their reproductive period. Managers attempt to implement seasons that allow for hunter satisfaction while limiting effects to reproduction and ensuring sustainable populations. To minimize illegal harvest, managers often attempt to set spring hunting seasons when gobbling activity is high and females are actively incubating nests. Gobbling activity varies significantly both temporally and spatially, and relationships between gobbling activity and reproductive phenology are unclear. We used autonomous recording units and Global Positioning System transmitters to monitor gobbling activity by male eastern wild turkeys (M. g. silvestris) and evaluate fine‐scale movements of male wild turkeys and nesting chronology of females on the Webb Wildlife Management Area Complex in South Carolina, USA, during 2015–2016. Based on 19,126 gobbles and movement ecology data from 99 wild turkeys (70 F, 29 M), we found no discernable pattern to support the hypothesis that gobbling activity increases with onset of incubation by females. We also observed no definable relationship between daily movements of males and gobbling activity, likely driven by the considerable daily variability in gobbling activity. We noted apparent lags in gobbling activity relative to nest initiation (onset of laying), and offer that understanding mechanisms underlying these apparent lags may be important to improving our understanding of reproductive ecology in wild turkeys. Research evaluating confounding influences of hunting activity and male mortality during the breeding season on gobbling activity and wild turkey population dynamics is warranted. © 2018 The Wildlife Society.

Population trends of Peregrine Falcon in Northern Spain – Results of a long-term monitoring project

Abstract We monitored Peregrine Falcon (Falco peregrinus) population in Bizkaia, Northern Spain, during two decades (1998–2017). Our population increased from 34 to 47 territorial pairs, as did other European populations until the first years of the 21st century, and then declined until 34 territorial pairs in 2017. The combination of catastrophic events (Prestige oil spill), increasing rain in winter and spring, and direct and indirect mortality factors significantly affected incubation onset, productivity and population stability, which in turn could impact on the floater population. Rain in February significantly affected incubation onset, which showed a slight positive trend during the last decade. Juvenile females laid 12 days later than adults, and each adult female started incubation in the same dates every year. However, the proportion of juvenile females did not significantly increase as might have been expected. Moreover, productivity was inversely related to incubation onset dates. Rain in April and May also affected productivity, and combined with short term extreme weather events determined a decreasing productivity during the last decade. Moreover, apart from human persecution (which caused 40.30% of the known deaths of Peregrines), we found 18 cases of breeders affected by infectious diseases, also related to weather. The combined effects of these factors, and the low availability of adequate nesting sites, negatively affected (i) territorial populations, (ii) productivity, and (iii) floater population, which in turn also determined territorial population and productivity.