Annual Movement Research Articles

Nomadic Movement of Mongolian Gazelles Identified through the Net Squared Displacement Approach

The Mongolian gazelles (Procapra gutturosa) that inhabit Mongolia's steppe and semi-desert travel several hundred kilometers each year. Their movement pattern has been considered nomadic, but the details of their movement patterns remain unclear. The aim of this study is to gain an overall perspective of the movement of Mongolian gazelles, which experience diverse environmental conditions with large interannual variations across their continuous distribution range. Based on net squared displacement (NSD) modeling approach, the mixed migration type was the most observed type in the statistical assignment among five movement types, and some movements were assigned into the migration or sedentary. However, NSD seasonal change was irregular in the most annual movements of gazelles, suggesting the nomadic movements of individuals. Most gazelles tracked for more than a year changed their movement types annually, and the movement period differed among individuals. These results also support nomadic movement of the species, although some difficulties of modeling nomadism by the NSD approach were revealed.

Migratory patterns and settlement areas revealed by remote sensing in an endangered intra-African migrant, the Black Harrier (Circus maurus).

Annual movements have been widely described for birds migrating across the Americas and between Eurasia and Africa, yet relatively little information exists for intra-African migrants. Identifying the areas used throughout a species annual cycle by understanding migratory patterns and settlement areas during breeding and non-breeding seasons is essential for conservation initiatives. Here, we describe for the first time, the migratory patterns and settlement areas of an endangered raptor endemic to Southern Africa, the Black Harrier (Circus maurus). From 2008 to 2015, thirteen breeding adult Black Harriers were trapped in south-western South Africa and fitted either with a GPS-GSM or with a PTT tracker device. Adults were monitored for 365 ± 198 days (range: 56–819 days) revealing great individual variability in annual movements. Most Black Harriers performed an unusual West-East migration from their breeding areas, but routes of all migrating individuals covered the entire southern land area of South Africa and Lesotho. The distance travelled averaged 814 ± 324 km, but unlike many other species, migrants travelled faster during post-breeding (i.e. austral summer) (207.8 ± 113.2 km.day-1) than during pre-breeding (i.e. austral winter/spring) migrations (143.8 ± 32.2 km.day-1). Although most marked individuals displayed movements similar to those that bred following pre-breeding migrations, only two of thirteen were confirmed as breeders the year after being tagged. This suggests that individuals may sometimes take a sabbatical year in reproduction, although this requires confirmation. Most tagged birds died on migration or during the non-breeding season. Adults frequently returned to the same non-breeding settlement areas, and often used up to 3 different locations an average of about 200 km apart. On the other hand, there was wide variation in distance between subsequent reproductive events. We discuss the implications of our study for the conservation of Black Harriers and more broadly for intra-African bird migrants.

Characterization of swine movements in the United States and implications for disease control

Understanding between-farm movement patterns is an essential component in developing effective surveillance and control programs in livestock populations. Quantitative knowledge on movement patterns is particularly important for the commercial swine industry, in which large numbers of pigs are frequently moved between farms. Here, we described the annual movement patterns between swine farms in three production systems of the United States and identified farms that may be targeted to increase the efficacy of infectious disease control strategies. Research results revealed a high amount of variability in movement patterns across production systems, indicating that quantities captured from one production system and applied to another may lead to invalid estimations of disease spread. Furthermore, we showed that targeting farms based on their mean infection potential, a metric that captured the temporal sequence of movements, substantially reduced the potential for transmission of an infectious pathogen in the contact network and performed consistently well across production systems. Specifically, we found that by targeting farms based on their mean infection potential, we could reduce the potential spread of an infectious pathogen by 80% when removing approximately 25% of farms in each of the production systems. Whereas other metrics, such as degree, required 26–35% of farms to be removed in two of the production systems to reach the same outcome; this outcome was not achievable in one of the production systems. Our results demonstrate the importance of fine-scale temporal movement data and the need for in-depth understanding of the contact structure in developing more efficient disease surveillance and response strategies in swine production systems.

Flexible timing of annual movements across consistently used sites by Marbled Godwits breeding in Alaska

AbstractThe study of avian movement has detailed a spectrum of strategies for the timing and use of sites throughout the annual cycle, from near randomness to complete consistency. New tracking devices now permit the repeated tracking of individual animals throughout the annual cycle, detailing previously unappreciated levels of variation within migratory systems. Godwits (genus Limosa) have featured prominently in studies of avian migration, but information derived from repeated tracking of individuals is limited. The Marbled Godwit subspecies Limosa fedoa beringiae breeds on the central Alaska Peninsula, and little is known about basic aspects of its migration ecology, including the repeatability with which this population times its annual migratory movements or uses migratory and nonbreeding sites. To address these questions, we equipped 9 Marbled Godwits breeding at a site near Ugashik, Alaska, with solar-powered satellite transmitters. We tracked individuals from July, 2008 to October, 2015 and obtained repeat migratory tracks from 5 of these birds. Individuals exhibited high fidelity to breeding, nonbreeding, and migratory stopover sites across years, but in contrast to congeners that conduct consistently timed, long, nonstop migrations, beringiae Marbled Godwits exhibited low levels of individual- or population-level repeatability in the timing of migratory movements. Their relatively short migrations may enable the integration of local environmental cues, potentially facilitating individual flexibility in the timing of annual migratory movements. Curiously, if local cues ultimately drive the timing of Marbled Godwit migratory movements, the population’s relatively constrained distribution during both the breeding and nonbreeding season should serve to synchronize birds if they are responding to similar cues. That our sample of Marbled Godwits nonetheless exhibited within- and between-year variation in the timing of their migratory movements suggests a complex integration of annually variable internal and external cues.

Estimability of migration survival rates from integrated breeding and winter capture-recapture data.

Long‐distance migration is a common phenomenon across the animal kingdom but the scale of annual migratory movements has made it difficult for researchers to estimate survival rates during these periods of the annual cycle. Estimating migration survival is particularly challenging for small‐bodied species that cannot carry satellite tags, a group that includes the vast majority of migratory species. When capture–recapture data are available for linked breeding and non‐breeding populations, estimation of overall migration survival is possible but current methods do not allow separate estimation of spring and autumn survival rates. Recent development of a Bayesian integrated survival model has provided a method to separately estimate the latent spring and autumn survival rates using capture–recapture data, though the accuracy and precision of these estimates has not been formally tested. Here, I used simulated data to explore the estimability of migration survival rates using this model. Under a variety of biologically realistic scenarios, I demonstrate that spring and autumn migration survival can be estimated from the integrated survival model, though estimates are biased toward the overall migration survival probability. The direction and magnitude of this bias are influenced by the relative difference in spring and autumn survival rates as well as the degree of annual variation in these rates. The inclusion of covariates can improve the model's performance, especially when annual variation in migration survival rates is low. Migration survival rates can be estimated from relatively short time series (4–5 years), but bias and precision of estimates are improved when longer time series (10–12 years) are available. The ability to estimate seasonal survival rates of small, migratory organisms opens the door to advancing our understanding of the ecology and conservation of these species. Application of this method will enable researchers to better understand when mortality occurs across the annual cycle and how the migratory periods contribute to population dynamics. Integrating summer and winter capture data requires knowledge of the migratory connectivity of sampled populations and therefore efforts to simultaneously collect both survival and tracking data should be a high priority, especially for species of conservation concern.

Seasonal survival and migratory connectivity of the Eurasian Oystercatcher revealed by citizen science

AbstractMigratory connectivity describes linkages between breeding and non-breeding areas. An ongoing challenge is tracking avian species between breeding and non-breeding areas and hence estimating migratory connectivity and seasonal survival. Collaborative color-ringing projects between researchers and citizen scientists provide opportunities for tracking the annual movements of avian species. Our study describes seasonal survival and migratory connectivity using data from more than 4,600 individuals with over 51,000 observations, predominantly collected by citizen scientists. Our study focuses on the Eurasian Oystercatcher (Haematopus ostralegus), a species that has experienced a substantial and ongoing decline in recent decades. Multiple threats have been described, and given that these threats vary in space and time, there is an urgent need to estimate demographic rates at the appropriate spatio-temporal scale. We performed a seasonal multi-state (5 geographical areas within The Netherlands) live- and dead-recoveries analysis under varying model structures to account for biological and data complexity. Coastal breeding populations were largely sedentary, while inland breeding populations were migratory and the direction of migration varied among areas, which has not been described previously. Our results indicated that survival was lower during winter than summer and that survival was lower in inland areas compared with coastal areas. A concerning result was that seasonal survival of individuals over-wintering in the Wadden Sea, an internationally important site for over-wintering shorebirds, appeared to decline during the study period. We discuss the outcomes of our study, and how citizen science was integral for conducting this study. Our findings identify how the demographic rates of the oystercatcher vary in space and time, knowledge that is vital for generating hypotheses and prioritizing future research into the causes of decline.

Ground-based remote-sensing techniques for diagnosis of the current state and recent evolution of the Monte Perdido Glacier, Spanish Pyrenees

ABSTRACTThis work combines very detailed measurements from terrestrial laser scanner (TLS), ground-based interferometry radar (GB-SAR) and ground-penetrating radar (GPR) to diagnose current conditions and to analyse the recent evolution of the Monte Perdido Glacier in the Spanish Pyrenees from 2011 to 2017. Thus, this is currently one of the best monitored small glacier (<0.5 km2) worldwide. The evolution of the glacier surface was surveyed with a TLS evidencing an important decline of 6.1 ± 0.3 m on average, with ice losses mainly concentrated over 3 years (2012, 2015 and 2017). Ice loss is unevenly distributed throughout the study period, with 10–15 m thinning in some areas while unchanged areas in others. GB-SAR revealed that areas with higher ice losses are those that are currently with no or very low ice motion. In contrast, sectors located beneath the areas with less ice loss are those that still exhibit noticeable ice movement (average 2–4.5 cm d─1 in summer, and annual movement of 9.98 ma─1 from ablation stakes data). GPR informed that ice thickness was generally <30 m, though locally 30–50 m. Glacier thinning is still accelerating and will lead to extinction of the glacier over the next 50 years.

Study on the role of annual movements of Arabian subtropical high pressure in the late start of precipitation in southern and southwestern Iran

According to Iran geographical location and the general circulation of the atmosphere (or atmospheric circulation), rainfall starts in many parts early in autumn and ends in mid or late spring based on the latitude. Due to the dominating synoptic conditions during some years, rainfall starts earlier than the normal conditions, and during some years, rainfall starts later than the normal conditions. Such synoptic conditions showed that the start of rainfall, especially in the south and southwest of Iran, is closely related to the location and displacement of Arabian subtropical high pressure in autumn. A study conducted on rainfall beginning day of 30 stations in a statistical period in 36 regions in south and southwest of Iran showed that during 12 years of rainfall began later than normal conditions. Arabian subtropical high pressure was extracted 1000, 850, and 700 hPa at four sea levels since September 15 to the beginning day of rainfall. This study showed that during those years when rainfall began later than normal, there were three general states. During some years, the high pressure system has been out of the southwest of Iran later than normal conditions. In a number of years, the high pressure system has left the area, but has moved westward, or the southern border of the Persian Gulf. The governing synoptic conditions of these three patterns have made it impossible for any rainfall system entering the region. In these patterns, Sudan low pressure system has been blocked as the most effective rainfall system in the southern latitude on Sudan and Ethiopia, and it is not possible to expand on the region or move to another route. In the three patterns, Arabian subtropical high pressure generally has an orbital expansion, and in this way, Mediterranean trough has no potential to expand southward. As a result, instability cannot be transferred to the region.

Annual cycle of White-winged Scoters (Melanitta fusca) in eastern North America: migratory phenology, population delineation, and connectivity

Understanding full annual cycle movements of long-distance migrants is essential for delineating populations, assessing connectivity, evaluating crossover effects between life stages, and informing management strategies for vulnerable or declining species. We used implanted satellite transmitters to track up to 2 years of annual cycle movements of 52 adult female White-winged Scoters (Melanitta fusca (Linnaeus, 1758)) captured in the eastern United States and Canada. We used these data to document annual cycle phenology; delineate migration routes; identify primary areas used during winter, stopover, breeding, and molt; and assess the strength of migratory connectivity and spatial population structure. Most White-winged Scoters wintered along the Atlantic coast from Nova Scotia to southern New England, with some on Lake Ontario. White-winged Scoters followed four migration routes to breeding areas from Quebec to the Northwest Territories. Principal postbreeding molting areas were in James Bay and the St. Lawrence River estuary. Migration phenology was synchronous regardless of winter or breeding origin. Cluster analyses delineated two primary breeding areas: one molting area and one wintering area. White-winged Scoters demonstrated overall weak to moderate connectivity among life stages, with molting to wintering connectivity the strongest. Thus, White-winged Scoters that winter in eastern North America appear to constitute a single continuous population.

Estimating Flight Distance of Platypus koryoensis (Coleoptera: Curculionidae) by Mark-Release-Recapture and Its Validation by Field Observation.

Korean oak wilt (KOW) is vectored by the beetle Platypus koryoensis (Murayama) (Coleoptera: Curculionidae), a native species of Korea, whose dispersal distance is a key factor determining the spread of damage by KOW. To estimate dispersal distance at stand level, we conducted a mark-release-recapture (MRR) experiment and validated its results using an independent data. Sticky traps were attached to the trunks of oak trees up to 48.8 m from the release point. Beetles were marked with different three fluorescent powders by date and released, and the number of recaptured beetles was counted 90 min after release. To validate the flight distance, annual mean dispersal distance of P. koryoensis population was analyzed using GPS coordinates of oak trees with the symptom of KOW recorded in the field from 2012 to 2014 in independent oak stands that have been damaged by KOW since 2012. The beetles were recaptured only on the day they were released, suggesting that the beetles only make one flight. The percentage of recaptured beetles was 6.0 ± 1.6%. The mean dispersal distance was 18.0 ± 1.3 m, and more than 85% of recaptured beetles were caught within 25 m. Annual movement distances in infested stands were 24.1 and 19.9 m from 2012 to 2013 and 2013 to 2014, respectively, similar to the dispersal distance obtained from our MRR experiment. Our results showed that the dispersal distance of P. koryoensis estimated by MRR is a useful process for predicting the spread of areas damaged by KOW.

Extreme Value-Based Methods for Modeling Elk Yearly Movements

Species range shifts and the spread of diseases are both likely to be driven by extreme movements, but are difficult to statistically model due to their rarity. We propose a statistical approach for characterizing movement kernels that incorporate landscape covariates as well as the potential for heavy-tailed distributions. We used a spliced distribution for distance travelled paired with a resource selection function to model movements biased toward preferred habitats. As an example, we used data from 704 annual elk movements around the Greater Yellowstone Ecosystem from 2001 to 2015. Yearly elk movements were both heavy-tailed and biased away from high elevations during the winter months. We then used a simulation to illustrate how these habitat effects may alter the rate of disease spread using our estimated movement kernel relative to a more traditional approach that does not include landscape covariates. Supplementary materials accompanying this paper appear online.

Aircraft noise and self-assessed mental health around a regional urban airport: a population based record linkage study

BackgroundLimited evidence suggests that residential exposure to aircraft noise negatively influences population mental health around large airports, but it is not known whether the same is true for smaller airports. We investigated whether residential exposure to aircraft noise near a regional urban airport was associated with risk of chronic self-assessed mental ill health.MethodsThis is a cross-sectional study of 198,532 people aged 18 years and over living in Belfast, United Kingdom, enumerated at the 2011 Census. Residential exposure to aircraft noise (LAeq,16h) was assessed by linking Census records with modelled noise contours surrounding George Best Belfast City Airport (c.42,000 annual aircraft movements). Associations between noise and mental ill health were estimated using multiple logistic regression adjusting for demographic characteristics, socio-economic status and comorbidity.ResultsPrevalence of self-assessed mental ill health was greater in high noise (≥57 dB) compared to low noise (< 54 dB) areas (12.4% vs. 9.7%). We found no association between aircraft noise and risk of mental ill health after adjustment for socio-economic status (high vs. low noise odds ratio: 1.03 CI: 0.93, 1.14).DiscussionAssociations between aircraft noise and mental health have been reported near large airports at similar average noise levels to those observed here. Our findings indicate that the noise environment around this smaller airport (with fewer flights and no night flights) has little influence on population mental health.

Robust goal programming for multi-objective optimization of data-driven problems: A use case for the United States transportation command's liner rate setting problem

Robust goal programming (RGP) is a recently developed, powerful new optimization modeling technique that conjoins two widely accepted operations research disciplines: robust optimization (RO) and goal programming (GP). In lieu of applying a probability distribution over possible outcomes, an approach considered by stochastic programming, RO utilizes uncertainty sets to account for data uncertainty. This characteristic of RO is an important attribute because identifying such a probability distribution is challenging, at best. Given this RO context, RGP additionally incorporates GP, traditionally a deterministic procedure, to address optimization problems having multiple objectives. As such, RGP has potential to help address a wide array of data-driven applications, ranging from financial management to engineering design.As a motivating use case for the utility of an RGP approach, this paper demonstrates the applicability of RGP by way of the data-driven United States Transportation Command (USTRANSCOM) liner rate setting problem. USTRANSCOM is responsible for the technical direction and supervision of over $7 billion [1] of annual passenger, cargo, mobility, and personal property movements in support of the Department of Defense (DoD). Transporting people and material with both organic and contracted assets, USTRANSCOM supports DoD organizations and agencies on a reimbursable basis, annually setting and charging rates for air and liner (i.e., sea) transport for their customers and reimbursing the transportation providers accordingly. The Cost Recovery Branch within TCJ8, the Financial Management and Program Analysis staff organization for USTRANSCOM, annually sets liner shipping rates specific to each combination of origin, destination, commodity type, booking terms, and container size for the upcoming fiscal year (FY). As a government entity, USTRANSCOM seeks to neither make a profit nor operate at a loss in any given FY. The current rate setting methodology assumes existing data is deterministic, resulting in process inaccuracies that contribute to unexpected surpluses or deficits each FY. Moreover, the current method fails to consider an additional USTRANSCOM objective: meeting customer's expectations that liner rates will change annually in accordance with industry-specific inflation. Considering the different goals and inherent parametric variance, the use case herein incorporates a decision maker's risk preference regarding parametric variability via a priori analysis to inform RGP techniques and improve the USTRANSCOM liner rate setting process.

Fluctuating food resources and home ranges in brown hyaenas living in a semi‐arid environment

AbstractWhilst food availability influences space use by animals, how fluctuating resources influence the location of home ranges and space use patterns is little understood. In this study, we first determined the home range of brown hyaenas (Parahyaena brunnea) living inside, and adjacent to, the Makgadikgadi Pans National Park, Botswana. We then examined home range use and how home range fidelity varied depending on the spatio‐temporal variability of available resources that were important for brown hyaenas. Finally, we determined if there was any variation in space use between male and female brown hyaenas. We found that brown hyaenas lived in well‐defined home ranges and showed strong spatial associations with other group members. Brown hyaenas shifted their seasonal home ranges to match food distribution. Hyaenas living in variable food environments demonstrated greater fluctuations in seasonal home range sizes and lower levels of home range retention than individuals from clans in more stable food environments. While home range edges remained more stable for clans located in areas with more food, they still showed a high degree of spatial plasticity in seasonal and annual movements in response to food availability and distribution over time. Clans living inside the Makgadikgadi Pans National Park did not defend an area sufficiently large to provide adequate food resources all year and individuals foraged into adjacent clan ranges when food was scarce. Hyaenas in clans outside Makgadikgadi Pans National Park lived in an area that contained adequate food resources all year. Gender did not influence space use by brown hyaenas.

Seasonal differences in energy expenditure, flight characteristics and spatial utilization of Dalmatian Pelicans Pelecanus crispus in Greece

Animals typically adjust their behaviour to their changing environment throughout the annual cycle, modulating key processes such as the timing of breeding and the onset of migration. Such behavioural changes are commonly manifested in the movements and the energetic balance of individuals in relation to their species‐specific physiological characteristics, habitat attributes and the environmental properties of their distribution ranges. We used GPS and acceleration data collected using transmitters on free‐ranging birds to quantify annual movement patterns and estimate energy expenditure of the Dalmatian Pelican Pelecanus crispus, a large, soaring avian species which performs short‐distance migration and spends its entire annual cycle in mid‐latitudes. To assess the representativeness of our results, the transmitter effect was also tested. We found that daily trends in the overall dynamic body acceleration (ODBA; a proxy for energy expenditure) differed among seasons, with the highest values occurring during spring and the lowest during winter. Long inter‐lake flights were very rare in winter, and the number of flights and ODBA during spring was higher than during summer, suggesting greater motivation to move in spring. Although transmitters may have affected the birds, as none of the tagged birds bred, we found seasonal differences in behaviour and activity level. The observed patterns in differences in activity levels, long‐distance flights and flight characteristics between seasons suggest an annual rhythm of energy expenditure. These findings allow a better understanding of bird phenology, specifically regarding adaptations to wintering in a cold climate by reducing movement‐driven energy expenditure. Finally, the identification of periods with high and low energy expenditure may guide future conservation efforts by adjusting conservation plans in accordance with changing needs during the annual cycle.

Impact of Hajj on Global Health Security.

With the human society transfers from scattered pieces to a society as a whole and the advent of the aviation era, the occurrence of infectious diseases and their diffusion have led to international health security issues. As the world’s largest and irrevocable annual transnational religious movement, the Hajj and its connection with health security concerns have caught attention since the ancient times, because a huge population from all over the world gathers in the holy city of Mecca, which has tropical arid climate. Currently, the international community and international organizations are implementing multilevel governance with respect to the health security issues of the Hajj. Relevant agencies include the World Health Organization and its regional branches, International Red Cross and Red Crescent Movement (ICRC), the Ministry of Hajj as well as the Ministry of Health of Saudi Arabia, and the public health sectors/agencies in various countries that are involved with Hajj activities. The international community has successfully held the Hajj events, even when facing the challenges brought by some viral respiratory diseases such as SARS and MERS. The Hajj has become a rare opportunity for all stakeholders to improve their capabilities in international health security governance.

Movements and geographic distribution of juvenile bluefin tuna in the Northeast Atlantic, described through internal and satellite archival tags

Abstract From 2005 to 2010, 136 internal archival tags and 29 pop-up satellite archival tags were used to track juvenile Atlantic bluefin tuna in the Bay of Biscay. Information from 15 pop-up and 5 internal archival tags was recovered. The analysis was adapted for a common treatment of both types of tag data, allowing classification of overwintering distribution patterns, fidelity to the Bay of Biscay feeding area, as well as of horizontal and vertical habitat utilization. Results show substantial geographic dispersion from autumn to spring, with high habitat concentration in the Bay of Biscay during summer, when bluefin tuna inhabit in the mixed layer. Of the individuals that left the Bay of Biscay towards the end of the year, a high percentage returned the next year, suggesting a strong fidelity to the area. Thirty-three percent of records during the overwintering periods revealed residency in the Bay of Biscay and surrounding areas. Half of the fish overwintered in the mid-Atlantic, near the Azores or Madeira Islands, while three (17%) made trans-Atlantic round trips, and one individual travelled to and remained off the eastern coast of the United States. These findings challenge previous assumptions regarding the seasonality and annual movements of bluefin tuna from the Bay of Biscay, while demonstrating extensive spatio-temporal dispersion.

Linking events throughout the annual cycle in a migratory bird—non-breeding period buffers accumulation of carry-over effects

Annual cycles of animals consist of distinct life history phases linked in a unified sequence, and processes taking place in one season can influence an individual’s performance in subsequent seasons via carry-over effects. Here, using a long-distance migratory bird, the collared flycatcher Ficedula albicollis, we link events throughout the annual cycle by integrating breeding data, individual-based tracking, and stable-carbon isotopes to unravel the connections between different annual phases. To disentangle true carry-over effects from an individuals’ intrinsic quality, we experimentally manipulated the brood size of geolocator-tracked males prior to tracking. We did not find unambiguous differences in annual schedules between individuals of reduced and increased broods; however, in the following spring, the latter crossed the Sahara and arrived at the breeding grounds earlier. Individuals with higher absolute parental investment delayed their autumn migration, had shorter non-breeding residency period but advanced spring migration compared to individuals with lower breeding effort. Neither the local non-breeding conditions (as inferred from δ13C values) nor the previous breeding effort was linked to the timing of the following breeding period. Furthermore, while on migration, collared flycatchers showed a pronounced “domino effect” but it did not carry over across different migration seasons. Thus, the non-breeding period buffered further accumulation of carry-over effects from the previous breeding season and autumn migration. Our results demonstrate tight links between spatially and temporally distinct phases of the annual cycles of migrants which can have significant implications for population dynamics. Timing is everything! This holds true also for migratory animals which must time their annual movements, breeding and non-breeding seasons according to the environment they live in. However, perfect timing of a particular event can be hampered by past events. We studied connections between spatially and temporarily distinct annual phases in collared flycatchers, a small bodied bird which twice a year migrates between Europe and sub-Saharan Africa. We found tight links between individual’s parental investment and timing of autumn migration, but not spring migration. Similarly, the timing of autumn migration did not translate to influence the timing of spring migration. Thus, our results demonstrate that the non-breeding period may serve as a buffer to overcome high energy expenditure during the previous breeding season and prevent further accumulation of carry-over effects in migratory birds.

From single steps to mass migration: the problem of scale in the movement ecology of the Serengeti wildebeest.

A central question in ecology is how to link processes that occur over different scales. The daily interactions of individual organisms ultimately determine community dynamics, population fluctuations and the functioning of entire ecosystems. Observations of these multiscale ecological processes are constrained by various technological, biological or logistical issues, and there are often vast discrepancies between the scale at which observation is possible and the scale of the question of interest. Animal movement is characterized by processes that act over multiple spatial and temporal scales. Second-by-second decisions accumulate to produce annual movement patterns. Individuals influence, and are influenced by, collective movement decisions, which then govern the spatial distribution of populations and the connectivity of meta-populations. While the field of movement ecology is experiencing unprecedented growth in the availability of movement data, there remain challenges in integrating observations with questions of ecological interest. In this article, we present the major challenges of addressing these issues within the context of the Serengeti wildebeest migration, a keystone ecological phenomena that crosses multiple scales of space, time and biological complexity.This article is part of the theme issue 'Collective movement ecology'.

Factors affecting sustainable animal trypanosomosis control in parts of Kaduna State, Nigeria

This study examined the factors affecting sustainable trypanosomiasis control in parts of Kaduna State within the sub-humid savannah ecological zone of Nigeria. Focus group discussions were held with herdsmen and livestock owners (n=85). Questionnaire was administered to participants (n=25) and key-informants (n=5) were interviewed. Most respondents (80%) were Fulani by tribe who could read and write Hausa in Arabic text (ajami). Over 70% were permanent residents practicing transhumant animal husbandry. Animal trypanosomiasis (sammore), liverfluke (chiwon hanta), worm infestations (helminthosis), and foot and mouth disease (chiwon kafa baki) in Hausa and “boru” in Fulfulde were ranked in decreasing order of important livestock diseases mentioned. A trypanocide (in sachet) identified to be Berenil® was administered by livestock farmers themselves. Many livestock owners and some households had lost various numbers of cattle and herds because of animal trypanosomosis. Tsetse flies (kudan tsando) were said to be very common, yet many could not differentiate it from other haematophagous biting flies. During dry season, when forage and water shortage is imminent, there is migration to southern parts of Nigeria. Annual herd movement to rangelands in nearby Bauchi State was due to perceived increased tsetse fly population in wet season. In addition, about 80% of arable land was used for crop cultivation. More awareness and preference for pour-on and aerial spraying were higher than the use of traps, target or screens. Rearing of trypanotolerant breeds and zero grazing was never practiced. A private-public partnership in tsetse and animal trypanosomosis control using commercially available trypanocides and insecticide is feasible and should be effectively explored. Any sustainable control strategy envisaged should recognize the level of awareness of the disease and vectors and willingness of grassroots stakeholders to participate and adapt the control methods. Keywords: Awareness, livestock, indigenous knowledge, socio-economics, trypanosomosis control, tsetse fly