Diurnal brooding behavior of long-tailed tits （Aegithalos caudatus glaucogularis）

Brooding is a major breeding investment of parental birds during the early nestling stage, and has important effects on the development and survival of nestlings. Investigating brooding behavior can help to understand avian breeding investment strategies. From January to June in 2013 and 2014, we studied the brooding behaviors of long-tailed tits （Aegithalos caudatus glaucogularis） in Dongzhai National Nature Reserve, Henan Province, China. We analyzed the relationships between parental diurnal brooding duration and nestling age, brood size, temperature, relative breeding season, time of day and nestling frequencies during brooding duration. Results showed that female and male long-tailed tit parents had different breeding investment strategies during the early nestling stage. Female parents bore most of the brooding investment, while male parents performed most of the nestling feedings. In addition, helpers were not found to brood nestlings at the two cooperative breeding nests. Parental brooding duration was significantly associated with the food delivered to nestlings （F=86.10, dr=l, 193.94, P〈0.001）, and was longer when the nestlings received more food. We found that parental brooding duration declined significantly as nestlings aged （F=5.99, dr=-1, 50.13, P=0.018）. When nestlings were six days old, daytime parental brooding almost ceased, implying that long- tailed tit nestlings might be able to maintain their own body temperature by this age. In addition, brooding duration was affected by both brood size （F=12.74, dr=-1,32.08, P=0.001） and temperature （F=5.83, df=-l, 39.59, P=-0.021）, with it being shorter in larger broods and when ambient temperature was higher.

An unusual homing behavior found in the Sichuan Partridge during the early brooding period

In this study,we report an unusual homing behavior of the Sichuan Partridge(Arborophila rufipectus)at the Laojunshan National Nature Reserve,Sichuan Province,China.Hen Sichuan Partridges led the chicks back to the nests where they hatched in the evening and roosted there over night.This behavior lasted 6.7±4.3 nights(range=1–15;n=13)after the chicks hatched.At this stage,the hens became very vigilant to predators and human disturbance.If disturbed,they often abandoned the nests immediately and no longer returned thereafter.The ambient temperature at night during the early brooding period of Sichuan Partridge at our study site was^12.4°C.Our findings suggest that hen Sichuan Partridges may make trade-offs between nest predation risks versus the thermoregulatory needs of their young.

Key Techniques of Artificial Incubation and Brooding of Bonasa bonasia

The key techniques of artificial incubation and brooding of Bonasa bonasia during breeding technology promotion was summed up in the paper.Electric incubation and dielectric incubation,electric brooding and dielectric brooding were compared with each other.The results showed that the effect of dielectric inoculation was poor,and there were no significant difference between electric brooding and dielectric brooding.

Does social information affect the settlement decisions of resident birds in their second breeding attempt?A case study of the Japanese Tit(Parus minor)

Individuals may gather information about environmental conditions when deciding where to breed in order to maximize their lifetime fitness.They can obtain social information by observing conspecifics and heterospecifics with similar ecological needs.Many studies have shown that birds can rely on social information to select their nest sites.The location of active nests and the reproductive success of conspecifics and heterospecifics can provide accurate predictions about the quality of the breeding habitat.Some short-lived species can facultatively reproduce two and/or more times within a breeding season.However,few studies have focused on how multiplebrooding individuals select nest sites for their second breeding attempts.In this study,we use long-term data to test whether the Japanese Tit(Parus minor)can use social information from conspecifics and/or heterospecifics(the Eurasian Nuthatch Sitta europaea,the Daurian Redstart Phoenicurus auroreus and the Yellow-rumped Flycatcher Ficedula zanthopygia)to select a nest site for the second breeding attempt.Our results showed that the nest boxes occupied by tits on their second breeding attempt tended to be surrounded by more breeding conspecific nests,successful first nests of conspecifics,and fewer failed first nests of conspecifics than the nest boxes that remained unoccupied(the control group).However,the numbers of breeding heterospecific nests,successful heterospecific nests,and failed heterospecific nests did not differ between the nest boxes occupied by tits on their second breeding attempt and the unoccupied nest boxes.Furthermore,the tits with local successful breeding experience tended to choose areas with more successful first nests of conspecifics than those without successful breeding experience.Thus,we suggest that conspecifics'but not heterospecifics'social information within the same breeding season is the major factor influencing the nest site selection of Japanese Tits during second breeding attempts.

Do brood parasitic Common Cuckoos develop brood patches during the breeding season?

Many birds develop brood patches on their ventral apterium under hormonal regulation to effectively transmit body heat to eggs during incubation.The developed patch has several characteristics,including de-feathering,vascularization,and edema.However,little is known about whether avian brood parasites that do not incubate their eggs exhibit brood patch development during the breeding season.In this study,we measured the size of the ventral apterium in 114 Common Cuckoos(Cuculus canorus)captured in the field throughout the breeding season and examined the appearance of the ventral apterium to confirm the development of brood patches.We also examined whether morphological traits and various factors correlated with the size of the ventral apterium(sternal apterium and abdominal apterium)and how it changed during the breeding season.We found no clear signs of brood patch development in Common Cuckoos captured throughout the breeding season,indicating that they likely did not develop brood patches on the ventral apterium during this period.We also found that ventral apterium size was positively correlated with wing length and body weight.In addition,Common Cuckoos with newly growing feathers on the boundary of the ventral apterium with pteryla were frequently observed as seasons progressed to the end.In conclusion,Common Cuckoos exhibit neither brood patch development nor the vestigial characteristics of ancestral brood patches,except for the growth of feathers on boundary the ventral apterium.Further studies examining brood patches across different groups of avian brood parasites are valuable for enhancing our understanding of the developmental and physiological adaptations of avian brood parasites.

Common Cuckoo(Cuculus canorus)nestlings adapt their begging behavior to the host signal system

Common Cuckoos(Cuculus canorus)dependent on parental care for post-hatching demonstrate an intriguing ability to modify their begging vocalizations to ensure maximum care and resources from their interspecific foster parents.Here,we compared begging calls of the Common Cuckoo nestlings fed by four host species,the Grey Bushchat(Saxicola ferreus),Siberian Stonechat(Saxicola maurus),Daurian Redstart(Phoenicurus auroreus),and Oriental Magpie-robin(Copsychus saularis).Results showed that begging calls of the stonechat-,redstart-,and robin-cuckoo resemble those of host species'nestlings in various aspects like low frequency,high frequency,frequency bandwidth and peak frequency,while the bushchat-cuckoo chicks'begging calls were only comparable to their host species in terms of how long they lasted and their peak frequency.In addition,cuckoo nestlings raised in different host nests displayed significant variations in their begging calls in low and peak frequency.This study suggests that cuckoo nestlings do not mimic host species nestlings'begging calls throughout the nestling period,but may tune their begging calls according to host species,while begging calls vary with cuckoo and host species nestlings'ages.Future research should study the parents'reactions to these calls in different host species for a better understanding of the mechanisms underlying such adaptations.

Oriental Reed Warblers do not abandon Common Cuckoo chicks during prolonged nestling periods

The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra reproductive costs,they may be less willing to care for nestlings that have prolonged nestling periods.To test this hypothesis,the duration of feeding by Oriental Reed Warblers under natural conditions for their own nestlings was compared with the duration of feeding under natural conditions for Common Cuckoo nestlings and for artificially prolonged cuckoo nestlings.The results showed that Oriental Reed Warblers did not starve,drive away,or desert any of the nestlings in the experiment,and neither parent was left alone.Our experimental study indicates that both Oriental Reed Warbler parents were willing to care for nestlings with a prolonged nestling period(up to 30 days,twice the average duration time that the Oriental Reed Warblers fed their own chicks in natural conditions).However,further experiments and observations are required in other host bird species to examine whether both parents or one of the parents may exhibit the behavior of abandoning nestlings with a prolonged nestling period.

Double-brooding and annual breeding success of great tits in urban and forest habitats

Urban areas differ from natural habitats in several environmental features that influence the characteristics of animals living there.For example,birds often start breeding seasonally earlier and fledge fewer offspring per brood in cities than in natural habitats.However,longer breeding seasons in cities may increase the frequency of double-brooding in urban compared with nonurban populations,thus potentially increasing urban birds’annual reproductive output and resulting in lower habitat difference in reproductive success than estimated by studies focusing on first clutches only.In this study,we investigated 2 urban and 2 forests great tit Parus major populations from 2013 to 2019.We compared the probability of double-brooding and the total number of annually fledged chicks per female between urban and forest habitats,while controlling for the effects of potentially confounding variables.There was a trend for a higher probability of double-brooding in urban(44%of females)than in forest populations(36%),although this was not consistent between the 2 urban sites.Females produced significantly fewer fledglings annually in the cities than in the forest sites,and this difference was present both within single-and double-brooded females.Furthermore,double-brooded urban females produced a similar number of fledglings per season as single-brooded forest females.These results indicate that double-brooding increases the reproductive success of female great tits in both habitats,but urban females cannot effectively compensate in this way for their lower reproductive output per brood.However,other mechanisms like increased post-fledging survival can mitigate habitat differences in reproductive success.

A novel method to collect sperm from brood parasitic cuckoos:Urodeum stimulation(UroS)method

Sperm competition has been studied in numerous species as a representative example of postcopulatory sexual selection,where sampling sperm from male is the most basic and important step.Sperm collection can be tricky in birds,however,because unlike mammals,the genitals of birds are generally latent in the cloacal region and their characteristics vary among species.Various methods to collect sperm from different birds have been tested,such as cloacal massage,feces collection,and electro-stimulation,but their applicability varies depending on species.In this study,we introduced the urodeum stimulation method(UroS method)to collect sperm from Cuculus cuckoos,such as the Common Cuckoo(C.canorus).These species are expected to have interesting patterns of pair bonding and sperm competition because of their unique breeding strategy called brood parasitism;however,it remains unexplored.In this study,we described the application of our new method to expel semen from male common cuckoos,measured the volume of semen collected,checked the presence of sperm in the semen sample,and finally estimated its success rate among 82 males.Samples were successfully collected from 76 cuckoos(approximately 93%)and the colors and volumes of the samples were very diverse.Sperm was present in 43 of these samples(57%),showing a sperm observation rate approximately twice as high as that of the conventional cloacal massage method.We believe that this novel method will contribute to a better understanding of postcopulatory sexual selection in avian brood parasites and facilitate the process of sperm collection and artificial insemination in other medium-sized birds.

Timing of breeding as a determinant of nest success of the vulnerable Chestnut Seedeater(Sporophila cinnamomea)in grasslands of southern South America

The breeding traits of Sporophila seedeaters have been relatively well studied in recent years;nevertheless,a group of ten species in the genus,known as southern capuchinos,remain understudied.That is the case with Chestnut Seedeater(Sporophila cinnamomea),a species vulnerable to extinction,which breeds in the grasslands of southeast South America and,after reproduction,migrates towards the Cerrado region in central Brazil.Here,we investigated breeding ecology and calculated average clutch size,productivity,the sex ratio of nestlings,and estimated nest success.Then we tested(1)whether there is a relationship between the number of active nests and environmental variables,(2)whether the nestling sex ratio deviates from the 1:1 ratio,(3)whether clutch size varies between breeding seasons,and(4)whether the nest success is related to starting date,nest age,plant support,nest height from the ground,and clutch size.During two breeding seasons(October-March 2018-2020),we monitored 98 nests.We generated survival models with five interacting covariates to assess the survival of the nests.We recorded the entire breeding period for Chestnut Seedeater,which was estimated to be 4.6 months,similar to other migratory seedeaters.Clutch size did not differ between breeding seasons.The sex ratio of nestlings was not significantly different from the 1:1 ratio.Nest success was 31%,and predation was the leading cause of unsuccessful nests(83%).The daily survival rate was 0.95±0.01.The main predictor of nest survival was the covariate starting date.These findings,added to other aspects of the species’natural history described here,may help illuminate the ecology and behavior of Chestnut Seedeater and other southern endangered capuchinos,and grassland-dependent species of South America.

Diversity of parasitic cuckoos and their hosts in China

In this exposé we provide the first review of host use by brood parasitic cuckoos in a multiple-cuckoo system in China, based on our own long-term field data and a compilation of observations obtained from the literature. In total, we found that 11 species of cuckoos utilized altogether 55 host species. These hosts belong to 15 families, in which Sylviidae, Turdidae and Timaliidae account for 22.6%, 20.8% and 17.0% of parasitism records, respectively. The Common Cuckoo (Cuculus canorus) had the widest range of host species, accounting for 45.5% of the total number of parasitized species (25 in 10 families) of all parasitism records and is the most frequent brood parasite in the country. Cuckoo species differed in their egg coloration and the extent of egg polymorphism with most of them, e.g. the Common Cuckoo, the Lesser Cuckoo (C. poliocephalus) and the Plaintive Cuckoo (Cacomantis merulinus) laying well mimetic eggs with respect to their hosts based on human being’s visual observations, while others such as the Large Hawk-cuckoo (C. sparverioides), the Himalayan Cuckoo (C. saturatus) and the Asian Emerald Cuckoo (Chrysococcyx maculatus) usually laid non-mimetic eggs. The use of cuckoo hosts and egg color variation in China are compared with those in other parts of their ranges in Asia.

SSR Analysis of Three Species from Primary Parent and Their First Generation of Litopenaeus vannamei

Genetic variations of three species from primary parent （OI Q,SIS Q,Kona Bay Q） and their first filial generation （OI Z,SIS Z,Kona Bay Z） of Litopenaeus vannamei were detected using microsatellite marker technique.The amplified products of genomic DNA with 8 microsatellite makers indicated that 8 loci presents polymorphism,the number of total alleles were 28 in 6 species;the number of allele of every loci was 2 to 6;mean allele number （Na） was 3.5;expected heterozygosity value （He） were higher than observed heterozygosity value （Ho）;mean polymorphism information content （PIC） ranged from 0.479 4 to 0.769 9,which showed these 8 loci posses relatively high information content.Through analysis of genetic structure in primary parent and their first filial,allele and effective allele number,observed heterozygosity and expected heterozygosity values and mean polymorphism information content （PIC） in filial generation were little lower than their primary parents.However,genetic diversity of filial generation is not influenced,and still maintains a good heritability.

Observation on behavior of adult oriental white stork in nesting period

Based on the field observation on the parental behavior of Oriental White Stork (Ciconia boyciana) during their brooding period, this paper describes the breeding style, feeding behavior, water chicks, protect chicks, etc. A Ritual “behavior—Culmen Knocking/bill clattering” was observed and which is divided into three styles with deferent meanings. This behavior plays an important role during this season.

Eggs mimicry of Common Cuckoo (Cuculus canorus) utilizing Ashy-throated Parrotbill (Paradoxornis alphonsianus) host

Polymorphism in egg coloration is prominent in the Common Cuckoo (Cuculus canorus) and a common host, the Ashy-throated Parrotbill (Paradoxornis alphonsianus). Egg polymorphism has probably evolved as a consequence of frequency-dependent selection in both host and parasite, and has, according to human vision, resulted in discrete immaculate white, pale blue and blue egg phenotypes within a single population. However, egg mimicry assessment is not always straightforward, and previous studies have shown that human based comparisons applied to the coloration of bird eggs may be inadequate. Here, we objectively quantify egg color of both parasite and host by spectrophotometry and assess egg mimicry of the Common Cuckoo to the eggs of its Ashy-throated Parrotbill host. Our results revealed that egg reflectance spectra agree well with the assessment based on human vision that cuckoo eggs mimic those of the parrotbill host, in both visible (VIS) and ultraviolet (UV) ranges. However, the white cuckoo egg shows slightly poorer mimicry than the blue cuckoo egg in corresponding host clutches. We suggest that the white parrotbill egg morph (and subsequently the whitish cuckoo egg color) may have evolved after the evolution of the blue egg morph due to strong selection from parasites in the cuckoo-parrotbill system.

Species identification of sympatric cuckoo nestlings in a multiple-cuckoo system,China

Interaction between a parasite and its host could lead to a co-evolutionary arms race. Cuckoo-host system is among the most studied of all brood parasite systems, but the cuckoos of Asia, on the other hand, are much less well known. China has the most abundant cuckoo species in Asia. Many of these co-occur in sympatric areas, posing a potential risk of mis-identification of cuckoo nestlings, especially in Cuculus species. In this study we have provided a practical criterion to identify cuckoo nestlings species in the field and performed molecular phylogeny to confirm our empirical results. These results indicate that two distinct characteristics of cuckoo nestlings, i.e., the gape color pattern and feather traits can be considered as reliable species identification. To our knowledge, this is the first report for species identification of Cuculus nestlings through molecular analysis.

Thoreau's philosophy of “simplify”

The essay expounds the philosophy of Thoreau's "simplify" in aspect of meaning and reason.Closely connected with the relationship between human and nature,it enables us to see the point of a brooding,simple and sensible life of Thoreau.The end clarifies on a question:according to Thoreau,what is to have a simplify life? That's to care for little,listen to one's heart and do what one likes.The conclusion comes with an advocation that people keep a simple life with little greed,and take it as an ulti mate cure for the bothering life of today.

A survey to the distribution of the Scaly-sided Merganser(Mergus squamatus)in Changbai Mountain range(China side)

In 2008 and 2009,we made continuous and repeated breeding surveys of the Scaly-sided Merganser(Mergus squamatus)in the Changbai Mountain range(China side),using a combination of rubber-boat drifting and walking.Each survey consisted of a census of breeding pairs in the spring and broods in the summer.A total of 1553 km in length of 17 river stretches were surveyed in four different river systems of the Yalujiang,Songhuajiang,Tumenjiang and Mudanjiang rivers.A total of 1354 individuals of the Scaly-sided Merganser were recorded during the both surveys.The breeding density for all the stretches surveyed over both years averaged 0.26 ± 0.30 pairs per km;the population density in the spring averaged 0.75 ± 0.88 individuals per km.According to our survey results,we estimated that the breeding population in the Changbai Mountain range was about 170 breeding pairs of the Scaly-sided Merganser.Three major breeding sites of this bird were found in the Changbai Mountain range in these surveys.

Why do brood parasitic birds lay strong-shelled eggs?

Brood parasitic birds constitute a model system for the study of coevolution.Such parasites are unique by having evolved unusually thick eggshells for their body size.ick eggshells have been hypothesized to evolve as 1) a means of preventing damage to parasite eggs when the brood parasite lays its egg at a distance from the host clutch(the laying damage hypothesis);2) a consequence of host puncture ejection(the puncture resistance hypothesis);3) a means for the brood parasite to allocate calcium to development of a disproportionately large skeleto-muscular system in evicting parasite chicks(the chick vigour hypothesis);or 4) a means of protecting the cuckoo embryo from microorganisms in the nest of the host(the anti-bacterial protection hypothesis).Here we review the literature studying the evolutionary mechanisms promoting thick eggshells in avian brood parasites,and provide proposals for future studies to test their validity.Available data are insu cient to rigorously test exclusive predictions and assumptions of these not necessarily exclusive hypotheses,although the laying damage and the puncture resistance hypotheses seem to currently be the most well supported alternatives.We discuss how quanti cation of rejection modes(grasp ejection,puncture ejection and desertion) may disclose the validity of the puncture resistance hypothesis,and nally we provide perspectives for future research on testing this speci c hypothesis.

Using the nematode Caenorhabditis elegans as a model animal for assessing the toxicity induced by microcystin-LR

Among more than 75 variants of microcystin （MC）, microcystin-LR （MC-LR） is one of the most common toxins. In this study, the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied. C. elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L. The results showed that MC-LR could reduce lifespan, delay development, lengthen generation time, decrease brood size, suppress locomotion behavior, and decreases hsp-16-2-gfp expression. The endpoints of generation time, brood size, and percentage of the population expressing hsp-16-2-gfp were very sensitive to 1.0μg/L of MC-LR, and would be more useful for the evaluation of MC-LR toxicity. Furthermore, the tissue-specific hsp-16-2-gfp expressions were investigated in MC-LR-exposed animals, and the nervous system and intestine were primarily affected by MC-LR. Therefore, the generation time, brood size, and hsp-16-2-gfp expression in C. elegans can be explored to serve as valuable endpoints for evaluating the potential toxicity from MC-LR exposure.

Hawk mimicry does not reduce attacks of cuckoos by highly aggressive hosts

Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.