Individual consistency in spatiotemporal characteristics of migratory Whimbrels in the East Asian-Australasian Flyway

Many migratory birds exhibit interannual consistency in migration schedules,routes and stopover sites.Detecting the interannual consistency in spatiotemporal characteristics helps understand the maintenance of migration and enables the implementation of targeted conservation measures.We tracked the migration of Whimbrel(Numenius phaeopus)in the East Asian-Australasian Flyway and collected spatiotemporal data from individuals that were tracked for at least two years.Wilcoxon non-parametric tests were used to compare the interannual variations in the dates of departure from and arrival at breeding/nonbreeding sites,and the inter-annual variation in the longitudes when the same individual across the same latitudes.Whimbrels exhibited a high degree of consistency in the use of breeding,nonbreeding,and stopover sites between years.The variation of arrival dates at nonbreeding sites was significantly larger than that of the departure dates from nonbreeding and breeding sites.Repeatedly used stopover sites by the same individuals in multiple years were concentrated in the Yellow Sea coast during northward migration,but were more widespread during southward migration.The stopover duration at repeatedly used sites was significantly longer than that at sites used only once.When flying across the Yellow Sea,Whimbrels breeding in Sakha(Yakutia)exhibited the highest consistency in migration routes in both autumn and spring.Moreover,the consistency in migration routes of Yakutia breeding birds was generally higher than that of birds breeding in Chukotka.Our results suggest that the northward migration schedule of the Whimbrels is mainly controlled by endogenous factors,while the southward migration schedule is less affected by endogenous factors.The repeated use of stopover sites in the Yellow Sea coast suggests this region is important for the migration of Whimbrel,and thus has high conservation value.

Migratory mode transition of astrocyte progenitors in the cerebral cortex: an intrinsic or extrinsic cell process?

The cerebral cortex is comprised of properly localized cell types that exert their specific functions.In the developing brain,cells migrate from the germinal region to their functional locations(Silva et al.,2019;Cossart and Garel,2022).For example,neocortical excitatory neurons are generated in the cerebral ventricular and subventricular zones,move to the developing cortical plate via radial migration,and reside in a radial array of six neuronal layers(Oishi and Nakajima,2018).On the other hand,cortical interneurons are mainly generated in ganglionic eminences,migrate tangentially across the cerebral cortex,and reach their final destinations in the cortex(Lim et al.,2018).The failure of neuronal migration leads to defects in cortical layer formation.While the mechanisms of neuronal distribution have been well examined,how astrocytes are diffusely distributed in the cortex is still unclear.Astrocytes are glial cells in the cerebral cortex with several functions,including metabolic support and synapse formation(Abbott et al.,2006;Bosworth and Allen,2017;Allen and Lyons,2018).For example,astrocytes establish synaptic connectivity in the developing brain while they contact numerous synapses and maintain optimal neuronal activity in the adult brain.In the developing brain,astrocytes are primarily generated from radial glia after the neurogenic period.While a certain type of astrocyte called fibrous astrocytes populates the white matter,protoplasmic astrocytes migrate to the cortical plate during neural network formation.

Penetrative and migratory behavior of alkali metal in different binder based TiB_2-C composite cathodes

In electrolyte melts containing K at low temperature, the penetrative and migratory path of alkali metals （K and Na） in pitch, furan, phenolic aldehyde and epoxy based TiB2-C composite cathodes during the electrolysis process were studied by EDS and self-made modified Rapoport apparatus. The electrolysis expansion rates, the diffusion coefficients of the alkali metals and the corrosion rates of the composite cathode were also calculated and discussed. The results show that no matter what kind of binder is used, alkali metals have the same penetrative path in composite cathodes：firstly in pore, then in binder and finally in carbonaceous aggregates. K and Na penetrate into both binder and carbonaceous aggregates, which leads to the expansion of composite cathodes, and K has stronger penetration ability than Na. Electrolysis expansion rate of resin based composite cathode is smaller than that of pitch based composite cathodes, and so do the diffusion coefficient and corrosion rate. Resin based composite cathode has better resistance ability to the penetration of alkali metals than pith based composite cathode, and phenolic aldehyde based composite cathode exhibits the strongest resistance ability. The penetration rate, the diffusion coefficient of alkali metals in phenolic aldehyde based TiB2-C composite cathode and the corresponding corrosion rate are 4.72 mm/h, 2.24×10^-5 cm^2/s and 2.31 mm/a, respectively.

Migratory properties of cultured olfactory ensheathing cells by single-cell migration assay

Olfactory ensheathing cells （OECs） are a unique type of glial cells that have axonal growth-promoting properties. OEC transplantation has emerged as a promising experimental therapy of axonal injuries and demyelinating diseases. However, some fundamental cellular properties of OECs remain unclear. In this study, we found that the distinct OEC subpopulations exhibited different migratory properties based on time-lapse imaging of single isolated cells, possibly due to their different cytoskeletal organizations. Moreover, OEC subpopulations displayed different attractive migratory responses to a gradient of lysophosphatidic acid （LPA） in single-cell migration assays. Finally, we found that OEC subpopulations transformed into each other spontaneously. Together, these results demonstrate, for the first time to our knowledge, that distinct OEC subpopulations display different migratory properties in vitro and provide new evidence to support the notion of OECs as a single cell type with malleable functional phenotypes.

Morphological and migratory alterations in retinal Müller cells during early stages of hypoxia and oxidative stress

In the present study, retinal MOiler cells were cultured in vitro and treated with hydrogen peroxide （oxidative stressor） and cobalt chloride （hypoxic injury）. Following 24 hours of culture, compensatory hypertrophy was observed and cellular apoptosis increased. Hypoxia enhanced the migration ability of retinal MOiler cells and induced the expression of a-smooth muscle actin. Oxidative stress altered the morphology of MOiler cells when compared with hypoxia treatment.

Migratory flight of insect pests within a year-round distribution: European corn borer as a case study

Insect migratory flight differs fundamentally from most other kinds of flight behavior, in that it is non-appetitive. The adult is not searching for anything, and migratory flight is not terminated by encounters with potential resources. Many insect pests of agricultural crops are long-distance migrants, moving from lower latitudes where they overwinter to higher latitudes in the spring to exploit superabundant, but seasonally ephemeral, host crops. The migratory nature of these pests is somewhat easy to recognize because of their sudden appearance in areas where they had been absent only a day or two earlier. Many other serious pests survive hostile winter conditions by diapausing, and therefore do not require migration to move between overwintering and breeding ranges. Yet there is evidence of migratory behavior engaged in by several pest species that inhabit high latitudes year-round. In these cases, the consequences of migratory flight are not immediately noticeable at the population level, because migration takes place for the most part within their larger year-round distribution. Nevertheless, the potential population-level consequences can be quite important in the contexts of pest management and insect resistance management. As a case study, I review the evidence for migratory flight behavior by individual European corn borer adults, and discuss the importance of understanding it. The kind of migratory behavior posited for pest species inhabiting a permanent distribution may be more common than we realize.

Adjustment of the annual cycle to climatic change in a long-lived migratory bird species

Climate change has advanced the phenology of many organisms. Migratory animals face particular problems because climate change in the breeding and the wintering range may be asynchronous, preventing rapid response to changing conditions. Advancement in timing of spring migration may have carry-over effects to other parts of the annual cycle, simply because advancement of one event in the annual cycle also advances subsequent events, gradually causing a general shift in the timing of the entire annual cycle. Such a phenotypic shift could generate accumulating effects over the years for individuals, but also across generations. Here we test this novel hypothesis of phenotypic response to climate change by using long-term data on the Arctic tern Sterna paradisaea. Mean breeding date advanced by almost three weeks during the last 70 years. Annual arrival date at the breeding grounds during a period of 47 years was predicted by environmental conditions in the winter quarters in the Southern Ocean near the Antarctic and by mean breeding date the previous year. Annual mean breeding date was only marginally determined by timing of arrival the current year, but to a larger extent by arrival date and breeding date the previous year. Learning affected arrival date as shown by a positive correlation between arrival date in year （i ＋ 1） relative to breeding date in year （i） and the selective advantage of early breeding in year （i）. This provides a mechanism for changes in arrival date being adjusted to changing environmental conditions. This study suggests that adaptation to changing climatic conditions can be achieved through learning from year to year

DNA reveals long-distance partial migratory behavior in a cryptic owl lineage

Background: The Brown Hawk Owl complex is said to consist of three species,the Brown Boobook(Ninox scutulata),the Chocolate Boobook(Ninox randi) and the Northern Boobook(Ninox japonica),which includes the nominate migratory lineage Ninox japonica japonica and a mitochondrially distinct lineage of taxonomically uncertain status that has been recorded year-round at least in Taiwan.Overlap in ranges during migration and morphological similarity have led to difficulties in distinguishing the Brown Boobook from the Northern Boobook.Methods: PCR of cytochrome-b and Sanger sequencing of Ninox samples from Singapore and Brunei were used to determine sample identity.Results: Two out of four Singaporean samples and the Brunei sample were identified as Northern Boobooks.This is the first official record of this species in Singapore and represents a considerable range extension for the species.Further,the samples belong to the mitochondrially distinct lineage previously characterized in resident Taiwan Residents populations rather than to the well-known nominate migratory lineage.Conclusions: Our data show that the mitochondrial signature previously documented in resident Taiwan Residents populations of the Northern Boobook extends to migratory populations.This cryptic lineage may be more widespread in its breeding quarters,extending to the Chinese and Russian mainland,in which case the name florensis would apply to it.Further genetic and bioacoustic investigation is required to resolve the taxonomic status of this lineage.

Monitoring population dynamics of the migratory Red-crowned Crane (Grus japonensis) at Shuangtaihekou National Nature Reserve,northeastern China,from 1991 to 2012

We studied migratory Red-crowned cranes from 1991-2012 in order to track population dynamics and trends for these cranes over time at Shuangtaihekou,northeastern China.Our results show that the earliest arrival date of the Red-crowned Crane (Grus japonensis) was usually around 1 March in the spring and the latest departure date of the cranes around 8 November.The peak period for the number of cranes observed in the spring was 10-20 March over these 22 years.The staging period in the spring is about 25 days.Comparing the highest number of Red-crowned cranes observed in the spring,the migratory population was around 400 birds in the 1990s,then,increased to over 800 birds in 2000.For a short while,the population maintained itself around 600-800 birds.After that,the population started to decline,until during the most recent years,we observed around 400 birds at peak times of each season.Our results match a similar population change pattern observed in the wintering area for a western population,which has been declining since 2000.There is an urgent need to reinforce protection and management,as well as to maintain and improve the quality of their habitats.

EndoN treatment allows neuroblasts to leave the rostral migratory stream and migrate towards a lesion within the prefrontal cortex of rats

The binding properties of neural cell adhesion molecule are modulated by a polysialic acid moiety. This plays an important role in the migration of adult born neuroblasts from their area of origin, the subventricular zone, towards the olfactory bulb. Polysialisation increases the migration speed of the cells and helps to prevent the neuroblasts from leaving their migration route, the rostral migratory stream. Here, we evaluated the potential of intraventricular application of endoneuraminidase-N, an enzyme that specifically cleaves polysialic acid from neural cell adhesion molecule, in a rat model for structural prefrontal cortex damage. As expected, endoneuraminidase-N caused the rostral migratory stream to become wider, with a less uniform cellular orientation. Furthermore, endoneuraminidase-N treatment caused the neuroblasts to leave the rostral migratory stream and migrate towards the lesioned tissue. Despite the neuroblasts not being differentiated into neurons after a survival time of three weeks, this technique provides a solid animal model for future work on the migration and differentiation of relocated neuroblasts and might provide a basis for a future endogenous stem cell-based therapy for structural brain damage. The experiments were approved by the local animal care committee(522-27-11/02-00, 115;Senatorin für Wissenschaft, Gesundheit und Verbraucherschutz, Bremen, Germany) on February 10, 2016.

Migratory Behavior of Franklin’s Gulls (Larus pipixcan) in Peru

Information on the migratory pathways for birds is essential to the future citing of wind power facilities, particularly in off-shore waters. Yet, relatively little is known about the coastal or offshore migratory behavior of most birds, including Franklin’s gulls (Larus pipixcan), a long-distant migrant. We report observations along the coast of Peru made in November 2008 to determine where birds concentrated. Wind facilities can not avoid regions of high avian activity without knowing where that activity occurs. Migrant flocks of 250 to 50,000 were observed on coastal farmfields, dumps and estuaries, on beaches and mudflats, and up to 45 km offshore. Bathing and foraging flocks ranged in size from 20 to 500 birds, and most flocks were monospecific, with occasional grey-headed (Larus cirrocephalus) and band-tailed (L. belcheri) on the periphery. While previous notes report Franklin’s gulls foraging coastally, we found flocks feeding up to 45 km offshore by diving for prey or feeding on the water. The relative percentage of birds of the year varied in migrant flocks from zero to 14%, with lower numbers of young foraging aerially on insects (only 1%). The percentage of young feeding over the ocean decreased with increasing distance from shore;no young of the year were recorded at 36-44 km offshore. While there were large flocks of Franklin’s gulls resting on the water inshore, the number of gulls foraging offshore did not decline up to 45 km offshore. The presence of foraging flocks of Franklin’s gulls out to 45 km offshore, and occupying space from 0 to 20 m above the water, suggests that they would be vulnerable to offshore anthropogenic activities, such as offshore drilling and wind facilities.

A Speculation: Avian Migration and the K-T Extinction

One caveat to the dinosaur’s extinction is the conclusion that avian dinosaurs survived and became ancestors of birds. Their mobility enabled them to migrate great distances and find the nutrients needed to survive. Given this scenario, could the current observable migration of birds (the “dinosaurian offspring”) now be related? Migration is the regular seasonal movement undertaken by many species of birds, with the most common pattern, flying north in the Northern spring to breed in the temperate or Arctic summer and returning in the Northern autumn to wintering grounds in warmer regions of the south. The primary motivation for migration appears to be food. None of the major North-South migratory pathways fly over the Caribbean but three main fly ways, past to the west of the theorized K-T impact centre. Due to their ability to fly, the “avian Dinosaurs” adapted and survived very quickly in response to the disaster that marked the K-T boundary. It is an interesting speculation that the avian migration that we witness today is rooted in an event that occurred 66 million years ago! But it does explain why the migratory birds mostly fly from Polar summer to polar summer when they could just be as easily fly from Polar zone to the warmer equatorial region and back. In the recent article in Nature by Melanie During about identifying the late spring timing of the “Astro disaster”, it can be cited as consistent with my speculation. A late April early May Impact as suggested by During would have seen these migrations completely. The western migratory routes would have been found to be “luxurious” in vegetation in that first northern autumn after the “Astro-impact” while all eastern routes would have still been barren.

Unexpected divergence in magnetoreceptor MagR from robin and pigeon linked to two sequence variations

Birds exhibit extraordinary mobility and remarkable navigational skills,obtaining guidance cues from the Earth’s magnetic field for orientation and long-distance movement.Bird species also show tremendous diversity in navigation strategies,with considerable differences even within the same taxa and among individuals from the same population.The highly conserved iron and iron-sulfur cluster binding magnetoreceptor(MagR)protein is suggested to enable animals,including birds,to detect the geomagnetic field and navigate accordingly.Notably,MagR is also implicated in other functions,such as electron transfer and biogenesis of iron-sulfur clusters,raising the question of whether variability exists in its biochemical and biophysical features among species,particularly birds.In the current study,we conducted a comparative analysis of MagR from two different bird species,including the migratory European robin(Erithacus rubecula)and the homing pigeon(Columba livia).Sequence alignment revealed an extremely high degree of similarity between the MagRs of these species,with only three sequence variations.Nevertheless,two of these variations underpinned significant differences in metal binding capacity,oligomeric state,and magnetic properties.These findings offer compelling evidence for the marked differences in MagR between the two avian species,potentially explaining how a highly conserved protein can mediate such diverse functions.

准确影像定位在颈部食管腔外异物取出术的应用

目的分析颈部食管腔外异物的临床特点及准确影像定位在其诊断和治疗中的应用。方法回顾性分析2017年10月~2024年3月梅州市人民医院耳鼻咽喉科收治的10例颈部食管腔外异物患者,对颈胸部CT行多平面重建(multiplanar reconstruction,MPR),从横断位、冠状位、矢状位判断异物位置,选择合适的手术入路。结果10例颈部食管腔外异物,2例金属和1例木质异物为外伤进入颈部,7例鱼骨为误吞鱼骨迁移颈部。术前影像定位提示异物在环状软骨和甲状软骨周3例,甲状腺内1例,相对应颈椎周2例,胸锁乳突肌周2例,舌骨周2例。支撑喉镜下取出2例,经颈部切开入路取出7例,1例未取出转上级医院治疗。术中彩超协助定位3例。所有患者随访至今均痊愈。结论准确影像定位可为颈部食管腔外异物选择合适手术入路提供依据,术中若异物寻找困难,可借助术中彩超精确定位异物,为成功取出异物提供有力保障。

Runx2 regulates peripheral nerve regeneration to promote Schwann cell migration and re-myelination

Runx2 is a major regulator of osteoblast differentiation and function;however,the role of Runx2 in peripheral nerve repair is unclea r.Here,we analyzed Runx2expression following injury and found that it was specifically up-regulated in Schwann cells.Furthermore,using Schwann cell-specific Runx2 knocko ut mice,we studied peripheral nerve development and regeneration and found that multiple steps in the regeneration process following sciatic nerve injury were Runx2-dependent.Changes observed in Runx2 knoc kout mice include increased prolife ration of Schwann cells,impaired Schwann cell migration and axonal regrowth,reduced re-myelination of axo ns,and a block in macrophage clearance in the late stage of regeneration.Taken together,our findings indicate that Runx2 is a key regulator of Schwann cell plasticity,and therefore peripheral nerve repair.Thus,our study shows that Runx2 plays a major role in Schwann cell migration,re-myelination,and peripheral nerve functional recovery following injury.

Geochemical identification of a source rock affected by migrated hydrocarbons and its geological significance:Fengcheng Formation,southern Mahu Sag,Junggar Basin,NW China

The Fengcheng Formation is a crucial source rock and the primary reservoir for oil accumulation in the Mahu Sag.Crude oils are distributed throughout the Fengcheng Formation,ranging from the edge to the interior of the sag in the southern Mahu Sag.These crude oils originate from in-situ source rocks in shallowly buried areas and the inner deep sag.During migration,the crude oil from the inner deep sag affects the source rocks close to carrier beds,leading to changes in the organic geochemical characteristics of the source rocks.These changes might alter source rock evaluations and oil-source correlation.Based on data such as total organic carbon(TOC),Rock-Eval pyrolysis of source rocks,and gas chromatography-mass spectrometry(GC-MS)of the saturated fraction,and considering the geological characteristics of the study area,we define the identification characteristics of source rock affected by migrated hydrocarbons and establish the various patterns of influence that migrated hydrocarbons have on the source rock of the Fengcheng Formation in the southern Mahu Sag.The source rocks of the Fengcheng Formation are mostly fair to good,containing mainly Type II organic matter and being thermally mature enough to generate oil.Source rocks affected by migrated hydrocarbons exhibit relatively high hydrocarbon contents(S1/TOC>110 mg HC/g TOC,Extract/TOC>30%,HC:hydrocarbon),relatively low Rock-Eval Tmax values,and relatively high tricyclic terpane contents with a descending and mountain-shaped distribution.Furthermore,biomarker composition parameters indicate a higher thermal maturity than in-situ source rocks.Through a comparison of the extract biomarker fingerprints of adjacent reservoirs and mudstones in different boreholes,three types of influence patterns of migrated hydrocarbons are identified:the edge-influence of thin sandstone-thick mudstone,the mixed-influence of sandstone-mudstone interbedded,and the full-influence of thick sandstone-thin mudstone.This finding reminds us that the influence of migrated hydrocarbons must be considered when evaluating source rocks and conducting oil-source correlation.

Borohydride Ammoniate Solid Electrolyte Design for All-Solid-State Mg Batteries

Searching for novel solid electrolytes is of great importance and challenge for all-solid-state Mg batteries.In this work,we develop an amorphous Mg borohydride ammoniate,Mg(BH_(4))_(2)·2NH_(3),as a solid Mg electrolyte that prepared by a NH_(3)redistribution between 3D framework-γ-Mg(BH_(4))_(2)and Mg(BH_(4))_(2)·6NH_(3).Amorphous Mg(BH_(4))_(2)·2NH_(3)exhibits a high Mg-ion conductivity of 5×10^(-4)S cm^(-1)at 75℃,which is attributed to the fast migration of abundant Mg vacancies according to the theoretical calculations.Moreover,amorphous Mg(BH_(4))_(2)·2NH_(3)shows an apparent electrochemical stability window of 0-1.4 V with the help of in-situ formed interphases,which can prevent further side reactions without hindering the Mg-ion transfer.Based on the above superiorities,amorphous Mg(BH_(4))_(2)·2NH_(3)enables the stable cycling of all-solid-state Mg cells,as the critical current density reaches 3.2 mA cm^(-2)for Mg symmetrical cells and the reversible specific capacity reaches 141 mAh g^(-1)with a coulombic efficiency of 91.7%(first cycle)for Mg||TiS_(2)cells.

Chemokine platelet factor 4 accelerates peripheral nerve regeneration by regulating Schwann cell activation and axon elongation

Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.

The roles of macrophage migration inhibitory factor in retinal diseases

Macrophage migration inhibitory factor(MIF),a multifunctional cytokine,is secreted by various cells and participates in inflammatory reactions,including innate and adaptive immunity.There are some evidences that MIF is involved in many vitreoretinal diseases.For example,MIF can exacerbate many types of uveitis;measurements of MIF levels can be used to monitor the effectiveness of uveitis treatment.MIF also alleviates trauma-induced and glaucoma-induced optic nerve damage.Furthermore,MIF is critical for retinal/choroidal neovascularization,especially complex neovascularization.MIF exacerbates retinal degeneration;thus,anti-MIF therapy may help to mitigate retinal degeneration.MIF protects uveal melanoma from attacks by natural killer cells.The mechanism underlying the effects of MIF in these diseases has been demonstrated:it binds to cluster of differentiation 74,inhibits the c-Jun N-terminal kinase pathway,and triggers mitogen-activated protein kinases,extracellular signal-regulated kinase-1/2,and the phosphoinositide-3-kinase/Akt pathway.MIF also upregulates Toll-like receptor 4 and activates the nuclear factor kappa-B signaling pathway.This review focuses on the structure and function of MIF and its receptors,including the effects of MIF on uveal inflammation,retinal degeneration,optic neuropathy,retinal/choroidal neovascularization,and uveal melanoma.

Migration pattern of a population of Barn Swallows(Hirundo rustica)breeding in East Asian tropical region

Birds exhibit a high degree of migratory diversity,which is influenced by various ecological factors and life history strategies.Conducting studies on tropical bird migration,of which research is scarce,and comparing it with temperate birds can enhance our understanding of bird migration behaviour and its underlying mecha-nisms.In this study,we explored the migration behaviour of a breeding population of the Barn Swallow(Hirundo rustica)in Zhanjiang,southern China,a region located in the northern tropics,using light-level geolocators.From 2021 to 2023,we deployed geolocators on 92 breeding swallows and retrieved geolocators successfully from 23 individuals.These swallows all exhibited migratory behaviour,and wintering on various islands in Southeast Asia.They displayed sex differences in their wintering locations.All males concentrated in Borneo,while females primarily chose Borneo but also dispersed to the Philippines,South China Sea,and Vietnam for wintering.The studied swallow population adopted a seasonal migration pattern of“indirect in autumn,direct in spring”,bypassing the ecological barrier of the South China Sea in autumn and tending to directly cross it in spring migration.Moreover,the distance and duration of autumn migration was significantly longer than those of the spring migration.Compared to temperate Barn Swallows,the Barn Swallow population breeding in Zhanjiang adopts a pattern of“intra-tropical migration”and initiates autumn migration earlier.The formation of their migration pattern may be limited by ecological and physiological factors.