Spatial patterns of white stork (Ciconia ciconia) migratory phenology in the Iberian Peninsula

In contrast to the attention attracted by temporal trends of phenology, the spatial patterns of arrivals, departures or stays of trans-Saharan birds are still nowadays largely unknown in most of their European breeding areas. In the case of the white stork (Ciconia ciconia), some studies have attempted to describe its migratory patterns throughout some European countries but, to our knowledge, no one has related these patterns to some kind of explanatory variable which offers an ecologically-based explanation for the heterogeneous phenology observable among populations. Here, arrivals, departures and stays of this species, recorded in hundreds of Spanish localities, were related to a set of environmental, geographical, biological and spatial predictors, and modeled by multiple regression. The best model for arrival dates accounted for up to 34% of variability of data and pointed towards an earlier arrival in those populations located in south-western Iberia and with higher population densities. This last relationship is probably due to the competition for nest-site fidelity maintenance. However, no variable was able to explain properly the blurred spatial pattern recorded for departure dates. Departure decisions are strongly influenced by social behavior in this species and depend on collective decisions influenced by peculiar local environmental conditions of each year rather than macrogeographical gradients. Environmental, geographical or spatial variables also did not capture much of the observed variability in the length of the stays among populations. However, this variable was strongly related to the arrival and departure dates of populations. White storks stay longer in localities with earlier arrivals and, especially, later departures.     

Long-term satellite tracking of white stork ( Ciconia ciconia) migration: constancy versus variability

During satellite-tracking investigations of 140 white storks (Ciconia ciconia), one individual, the long-term world record holder among birds, was followed along 12 migratory journeys over a period of 10 years. This long-term study confirms what previous several-year tracking studies of white storks had indicated: there can be great variability from year to year in the choice of winter quarters as well as in the routes and times of migration, intermediate destinations and stop-over periods, but constancy of winter quarters and migration routes is also possible. The variability may well be caused by external factors, of which food supply is probably predominant.Communicated by F. Bairlein     

Census methods for White stork (Ciconia ciconia): bias in sampling effort related to the frequency and date of nest visits

Periodic censuses have been widely used to identify the population numbers and conservation status of many bird species. In order to be comparable, a census must be homogeneous through time. However, this requirement is not always possible. For this reason, studies addressing a possible bias in sampling efforts are very useful to correct such errors. In the present work, a standardized periodic monitoring of breeding White stork (Ciconia ciconia) at six Spanish colonies was conducted to estimate survey accuracy. We estimated the percentage of breeding pairs and productivity (number of chicks), i.e., accuracy, detected in each possible combination of number of visits as compared with the results obtained for the whole intensive monitoring, i.e., reality. Our results showed that single visits resulted in lower percentages of the number of breeding pairs and productivity detected compared with combinations of two or more visits. Nevertheless, one visit in a single month (April for the number of breeding pairs and June for productivity) did not show significantly lower results than the rest of the combinations of two or more visits. Early or late visits in the season might underestimate breeders by not accounting for either late-occupied or failed nests, respectively. In addition, the obvious increase in the probability of detection related with the number and the size of chicks is probably the reason why later visits in the season reported the highest value of productivity. In conclusion, the estimation bias presented in this study may be used to adjust sampling efforts in the census of the White stork.     

Effect of an ectoparasite on lay date, nest-site choice, desertion, and hatching success in the great tit (Pants major)

Ectoparasites are common in most bird species, but experimentalevidence of their effects on life-history traits is scarce.We investigated experimentally the effects of the hematophagoushen flea (Ceratophyllus gallinae) on timing of reproduction,nest-site choice, nest desertion, clutch size, and hatchingsuccess in the great tit (Parus major). When great tits wereoffered a choice on their territory between an infested anda parasite-free nest-box, they chose the one without parasites.When there was no choice, the great tits in a territory containingan infested nest-box delayed laying the clutch by 11 days ascompared with the birds that were offered a parasite-free nestingopportunity. The finding that there was no difference in phenotypictraits related to dominance between the birds nesting in infestedboxes and birds nesting in parasite-free boxes suggests thatthe delay is not imposed by social dominance. Nest desertionbetween laying and shortly after hatching was significandy higherin infested nests. There was no difference between infestedand parasite-free nests in clutch size, but hatching successand hence brood size at hatching were significantly smallerin infested nests. Nest-box studies of great tits have beenseminal in the development of evolutionary, ecological, andbehavioral theory, but recently a polemic has arisen in theliterature about the validity of the conclusions drawn fromnest-box studies where the naturally occurring, detrimentalectoparasites are eliminated by the routine removal of old nestsbetween breeding seasons. Our study suggests that this criticismis valid and that the evaluation of the effects of ectoparasitesmay improve our understanding of behavioral traits, life-historytraits, or population dynamics     

Low breeding success of the little egret (Egretta garzetta) near residential areas and in colonies exposed to gales: a comparison of colony in Sichuan,Southwest China,with literature

The breeding biology of the little egret (Egretta garzetta) was studied in 20 nests within the mixed-species breeding colonies at Nanchong, Sichuan, Southwest China, in 2006. By measuring a set of physical characteristics of vegetation at the nests and at a set of 20 randomly chosen sites we showed that birds preferentially used taller trees in areas with fewer shrubs of higher species diversity. Nests at lower locations in trees had marginally lower hatching success due to their destruction by humans; this destruction contributed marginally significantly to lowering of the total nesting success in all studied nests. Although gale winds also had a negative effect on breeding success, the anthropogenic influences were a greater factor in reproductive failure. We found similar effects in our review of literature on breeding success of the little egret from various geographical areas. Our results may be of use by conservation organizations in their actions to protect colonies of the little egret.     

越冬地东方白鹳繁殖生物学的初步研究

近年来,陆续在长江中下游越冬地发现东方白鹳(Ciconia boyciana)繁殖个体。为了了解该种在当地的繁殖对策和种群现状,2004-2006年在安庆市望江县武昌湖地区(116°51.15′-116°49.47′E,30°19.53′-30°19.79′N)对东方白鹳的繁殖生物学进行了研究。东方白鹳在当地开始营巢时间不一致,最早为2月5日,而受干扰的繁殖个体则延至5月6日。观察到的巢全在高压线塔上,巢高34.6±0.8m(n=11),巢间距908.8±1039.4m(n=6)。产卵期最早开始于2月11日,最晚6月21日,窝卵数4.2±0.4(4-5)枚(n=6)。育雏期71.0±16.1d(n=3),日育雏5.1±2.6(n=38),雏鸟离巢时间最早6月14日,最晚9月20日。2004和2005年东方白鹳在该地区共营巢8窝,产卵25枚,孵出雏鸟9只,出飞7只。繁殖失败5巢,其中,人工干扰造成4巢失败,高压电击毁1巢。繁殖不同时期,亲鸟的觅食、休息、警戒、取材、翻卵、育雏、交配、在巢、视野外行为时间分配差异显著,而飞翔、行走、理羽、击喙、整巢和其它行为差异不显著。雏鸟在发育的不同时期,觅食、飞翔、休息、整巢、在巢、行走、视野外行为时间分配差异显著,理羽、警戒、击喙和其它行为差异不显著     

Foraging behaviour and feeding success of the black-necked stork (Ephippiorhynchus asiaticus) in Dudwa National Park, Uttar Pradesh, India

Foraging behaviour of the black-necked stork (BNS) Ephippiorhynchus asiaticus was studied in 1996 and 1997 in Dudwa National Park (DNP), Uttar Pradesh, India. The storks were observed using tactile and visual techniques to catch fish. Of the 929 fish seen caught in 2 years, 894 (96%) were caught by a tactile mode of feeding and the remaining 35 (4%) by a visual mode of feeding. The rate of foraging attempts by BNS fluctuates with that of season in DNP and coincides with prey abundance. Immediately after the monsoon when the water level was high, BNS had to search for prey more often, as the prey became widespread. Whereas in summer when the water level decreased, the concentration of the fish was higher, which helps BNS to catch fish in quick succession. Prey behaviour and the condition of the wetland determined the selection of the tactile foraging technique among the BNS in DNP. The black-necked storks were more successful in the early hours of the day (06:00–10:00) and they were generally more successful or preferred to feed on medium-sized fish (i.e. 5–10 cm) in DNP. Prey profitability was highest for larger size fish and decreased as the prey size decreased. Principal component analysis showed that prey size, handling time of each prey, the month and water depth determined foraging success in 1996 and 1997.     

Using Corine Land Cover Habitat Database for the analysis of breeding bird habitat: case study of white storks (Ciconia ciconia) from northern Croatia

The purpose of this study was to find out whether a set of habitat characteristics, derived from the National Corine Land Cover (CLC) database of habitat types, could indicate the occurrence of white stork nests in a settlement. The analyses were performed for the settlements closer than 35 km from the Drava River (northern Croatia). Sixteen habitat characteristics were determined around 257 settlements occupied with white stork nests and 152 control sites without white stork nests within the same geographic region. We performed multivariate inspection of the data and a non-metric multidimensional preference analysis. The best variables for stork habitat selection were: distance to the nearest grassland habitat (P < 0.0001), distance to three nearest grassland habitats (P < 0.0001), altitude of the settlements above the sea level (P < 0.001), sum of distances to the three nearest agricultural mosaic habitats (P < 0.005) and standardized area proportion of forests (P < 0.05). The explanatory capacity of the model was 81.1%. We conclude that it is possible to define a small number of habitat characteristics derived from CLC database which can indicate the occurrence of white stork nests.     

Climate and spatio-temporal variation in the population dynamics of a long distance migrant, the white stork

1. A central question in ecology is to separate the relative contribution of density dependence and stochastic influences to annual fluctuations in population size. Here we estimate the deterministic and stochastic components of the dynamics of different European populations of white stork Ciconia ciconia. We then examined whether annual changes in population size was related to the climate during the breeding period (the 'tap hypothesis' sensu Saether, Sutherland & Engen (2004, Advances in Ecological Research, 35, 185 209) or during the nonbreeding period, especially in the winter areas in Africa (the 'tube hypothesis'). 2. A general characteristic of the population dynamics of this long-distance migrant is small environmental stochasticity and strong density regulation around the carrying capacity with short return times to equilibrium. 3. Annual changes in the size of the eastern European populations were correlated by rainfall in the wintering areas in Africa as well as local weather in the breeding areas just before arrival and in the later part of the breeding season and regional climate variation (North Atlantic Oscillation). This indicates that weather influences the population fluctuations of white storks through losses of sexually mature individuals as well as through an effect on the number of individuals that manages to establish themselves in the breeding population. Thus, both the tap and tube hypothesis explains climate influences on white stork population dynamics. 4. The spatial scale of environmental noise after accounting for the local dynamics was 67 km, suggesting that the strong density dependence reduces the synchronizing effects of climate variation on the population dynamics of white stork. 5. Several climate variables reduced the synchrony of the residual variation in population size after accounting for density dependence and demographic stochasticity, indicating that these climate variables had a synchronizing effect on the population fluctuations. In contrast, other climatic variables acted as desynchronizing agents. 6. Our results illustrate that evaluating the effects of common environmental variables on the spatio-temporal variation in population dynamics require estimates and modelling of their influence on the local dynamics.     

Magnetic resonance imaging and spectroscopy (MRI, MRS) of seasonal patterns of body composition: A methodological pilot study in White Storks (Ciconia ciconia)

Summary Here we present a systematic application of magnetic resonance imaging (in the following called MRI) and magnetic resonance spectroscopy (MRS) to the White Stork. The main aim was to demonstrate the annual cycle of fat deposition in the same individuals for comparison to wild conspecifics, to clarify the energy metabolism of this migratory species. To obtain sharp, high-contrast images of the interior of the body, the birds were kept still by enclosing them in simple plastic tubes with additional fixation of legs and head, avoiding the problematic sedation with drugs. Altogether 12 test birds (young storks) were monitored systematically for 15 months, to follow seasonal changes in the internal organs (mainly breast muscles) and tissues (mainly fat depots). At each examination 22 high-contrast pixel images representing serial dorsoventral sections through the body were generated with the computer program MatLab, after which the pixels per section image were converted to tissue components in cm² and the distances between consecutive sections used to calculate the tissue volumes in cm³. To measure the fat in the breast muscle spectroscopy was used to determine the fat : water ratio, from which changes in fat content could be derived. The study revealed pronounced seasonal changes in the visceral and cutaneous/subcutaneous fat depots, which precisely paralleled the annual variation in body weight of the birds (see also the preceding paper, Berthold et al. 2001). The breast muscles exhibited the prolonged growth typical of the juveniles of large species but no conspicuous change at the migration periods. In this project MRI and MRS proved to be successful methods that show great promise.

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Magnet-Resonanz-Tomographie und -Spektroskopie der jahreszeitlichen Muster der Körperzusammensetzung: Eine methodische Pilotstudie am Weißstorch (Ciconia ciconia)

Zusammenfassung In der vorliegenden Arbeit stellen wir eine systematische Anwendung der Magnet-Resonanz-Tomographie (Kernspin-Tomographie, im Folgenden MRT) und der Magnet-Resonanz-Spektroskopie (im Folgenden MRS) am Weißstorch vor. Hauptaufgabe war es, die Jahresperiodik der Fettdeposition an denselben Individuen zu ermitteln, um Aufschluss über den Energiehaushalt dieser Zugvogelart durch Vergleiche mit freilebenden Vögeln zu bekommen. Die erforderliche Ruhigstellung der Vögel zum Erreichen scharfer kontrastreicher Bilder des Körperinneren war in einfachen Plastikröhren mit zusätzlicher Fixierung von Beinen und Kopf möglich, so dass auf die problematische Sedierung mit Narkotika verzichtet werden konnte. Insgesamt 12 Versuchsvögel (Jungstörche) wurden 15 Monate lang systematisch auf jahresperiodische Veränderungen von inneren Organen (v. a. Brustmuskeln) und Geweben (v. a. Fettdepots) untersucht. Aus je 22 seriellen kontrastreichen dorsoventralen Schnittbildern durch den Vogelkörper ließen sich mit dem Computerprogramm MatLab Pixelbilder erstellen und dann die Pixel pro Schnittbild in Gewebeanteile in cm² umrechnen und anschließend aus den aufeinander folgenden Schnittbildern die Gewebevolumina in cm³ ermitteln. Für die Fettbestimmung im Brustmuskel wurde durch Spektroskopie das Verhältnis von Fett: Wasser bestimmt, aus dem Veränderungen des Fettgehalts abgeleitet wurden. Die Studie ergab ausgeprägte jahresperiodische Änderungen der viszeralen und kutanen/subkutanen Fettdepots, die genau parallel zum Jahresgang des Körpergewichts der Vögel verliefen (s. auch die vorangehende Arbeit, Berthold et al. 2001). Für die Brustmuskeln ergab sich ein für Jungvögel großer Arten typisches lang anhaltendes Wachstum, aber keine auffallende Veränderung zu den Zugperioden. MRT und MRS erwiesen sich in dieser Arbeit als erfolgreich und vielversprechend.

     

Nest position,breeding success and diet of the Black-crowned Night Heron,Nycticorax nycticorax in the Anzali Wetland,Northern Iran (Aves: Ardeidae)

Breeding ecology of the Black-crowned Night Heron (Nycticorax nycticorax) was studied in a mono-specific colony in the Anzali wetland, Northern Iran during the breeding season of 2016. The breeding period lasted from mid-May to late July. The average clutch size was 3.1±0.6 eggs and the breeding success 77.6%. No significant differences were found between nests built on trunks and those built on branches of trees. The clutch size and breeding success appeared to be independent of the structural variables of the nesting site (diameter of trees, height from the ground, height of nests from the canopy, nest number per tree, location of nests on trunks and branches). No significant difference was found between the timing of the start of incubation and the height of nests above the ground. The average vertical and horizontal distances between nests was one metre. Fish, particularly Carassius gibelio, dominated the diet of the nestlings.     

Climatic effects on the breeding phenology and reproductive success of an arctic-nesting goose species

Climate warming is pronounced in the Arctic and migratory birds are expected to be among the most affected species. We examined the effects of local and regional climatic variations on the breeding phenology and reproductive success of greater snow geese ( Chen caerulescens atlantica ), a migratory species nesting in the Canadian Arctic. We used a long-term dataset based on the monitoring of 5447 nests and the measurements of 19 234 goslings over 16 years (1989–2004) on Bylot Island. About 50% of variation in the reproductive phenology of individuals was explained by spring climatic factors. High mean temperatures and, to a lesser extent, low snow cover in spring were associated with an increase in nest density and early egg-laying and hatching dates. High temperature in spring and high early summer rainfall were positively related to nesting success. These effects may result from a reduction in egg predation rate when the density of nesting geese is high and when increased water availability allows females to stay close to their nest during incubation recesses. Summer brood loss and production of young at the end of the summer increased when values of the summer Arctic Oscillation (AO) index were either very positive (low temperatures) or very negative (high temperatures), indicating that these components of the breeding success were most influenced by the regional summer climate. Gosling mass and size near fledging were reduced in years with high spring temperatures. This effect is likely due to a reduced availability of high quality food in years with early spring, either due to food depletion resulting from high brood density or a mismatch between hatching date of goslings and the timing of the peak of plant quality. Our analysis suggests that climate warming should advance the reproductive phenology of geese, but that high spring temperatures and extreme values of the summer AO index may decrease their reproductive success up to fledging.     

The role of setts in badger (Meles meles) group size, breeding success and status of TB (Mycobacterium bovis)

This paper examines the relationship between the number of occupied setts in a badger social group territory and badger group size, breeding success, and status of infection with Mycobacterium bovis (TB). The data used were from a long-term epidemiological and ecological study of a high-density population of badgers Meles meles in south-west England. The number of occupied setts in a social group was significantly and positively related to the number of badgers caught in the social group, so that as a social group increases in size, badgers occupy more of the available setts. This relationship remained significant when numbers of adults, adult males and adult females were examined. The number of breeding females, number of cubs and sex ratio was not related to the number of occupied setts in a social group. It is possible that the advantages to breeding females of a larger number of setts available to breed in might be outweighed by the increased aggression found in larger groups. The TB score for prevalence and for incidence of social groups was significantly and positively related to the number of occupied setts in a social group, such that the more occupied setts there were in a territory, the higher the TB index of the group. Possibly the setts themselves contribute to the persistence of TB within social groups, or badgers infected with TB might show a difference in behaviour from uninfected badgers resulting in their increased use of outlying setts.     

Factors affecting the breeding success of the grey heron ( Ardea cinerea) in northern Poland

The aim of this study was to estimate the importance of factors affecting the breeding success of the grey heron (Ardea cinerea) in three colonies in the northern Poland (Mosty, Kiersity and Kty Rybackie), differentiated in population size, habitat type and feeding areas used by birds. The highest mean number of fledglings (39–51 days old) per nest in 2000–2002 combined was recorded at Kty Rybackie (3.2±0.91 SD). Lower values were recorded at Kiersity (2.5±1.11) and Mosty (2.8±1.20). Breeding success increased with the size of the heronry (r₇=0.77, P<0.05) and was the highest in the biggest, at Kty Rybackie (716–879 nests). In the studied colonies, the number of feeding visits was the most important factor affecting breeding success. At Kty Rybackie and Kiersity, chick mortality significantly decreased with increasing numbers of feeding visits per nest. The highest breeding success was recorded in the colonies with feeding areas situated nearby (Kty Rybackie and Mosty). Siblicide was also a very important reason of chick mortality in those colonies (54% and 32% chicks died in nests where sibling aggression was observed). Other factors, independent of the level of feeding, like predation, human disturbance, weather condition and experience of parent birds, seem to be of negligible importance.Communicated by F. Bairlein     

Aspects of the breeding ecology of the Purple Swamphen Porphyrio porphyrio in the wetland complex of Guerbes-Sanhadja,north-east Algeria

The Purple Swamphen Porphyrio porphyrio is a common rail that previously was little investigated in North Africa. From 2011 to 2013, its breeding ecology was studied at two natural wetlands in north-east Algeria, namely Garaet Hadj Tahar and Garaet Messaoussa. Numbers of Purple Swamphens at both localities peaked in late April and early May. Egg-laying started in early March, whereas hatching started in late March. Peak egg-laying took place in late March and early April, and peak hatching from mid-April to early May. There were significant differences in the size and weight of eggs between years and localities. The mean clutch size was 2.75 ± 0.70 eggs and it was not signifi- cantly different between localities and years. Mean hatching success was 51% and it was positively correlated to nest depth only at Garaet Hadj Tahar. Most nests were built in dense tufts of Typha angustifolia and Phragmites australis. The main nesting materials were Phragmites australis and Scirpus maritimus.     

Nest site, laying period, and breeding success of the Woodchat Shrike (Lanius senator) in Mediterranean France

Summary Breeding habitats in Mediterranean France consist in open, dry grasslands with a low and discontinuous grass layer and scattered bushes and trees. The choice of nest supports was largely opportunistic, the most abundant suitable nest support type (bush or tree) and the most abundant species being present at each study site have been used. About 75% of the nests were placed at heights between 1 and 3 m. Laying period lasted from 9 May until 6 July (peak of first clutches: 21–30 May). Mean clutch size was 5.14±0.82 eggs (n=114). Breeding success was independent from the site, the height and the concealment of nests. Mean survival rate of nests from laying to fledgling was 0.365. The main cause of low breeding success was high nest predation exerted by a rich guild of predators. The species is mainly threatened through dramatic habitat shrinkage due to pastoralism reduction leading to closures of lightly bushed grasslands in Mediterranean France.

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Nistplatzwahl, Legeperiode und Bruterfolg des Rotkopfwürgers (Lanius senator) in Südfrankreich

Zusammenfassung Als Bruthabitat bevorzugt der Rotkopfwürgers im mediterranen Südfrankreich offene und trockene Graslandlandschaften mit niedrigem oder lückigem Grasbewuchs und einzelstehenden Büschen und/oder Bäumen. Häufigster Nestträger ist die jeweils im Brutterritorium häufigste Baum- oder Buschart. Ungefähr 75% der Nester standen zwischen 1 und 3 m über Boden. Die Legeperiode reichte vom 9. Mai bis 6. Juli (Gipfel der Erstgelege am 21.–30. Mai und der Ersatzgelege am 20.–24. Juni). Die Gelegegröße bestand aus 3 bis 7, meist 5 Eier (Erstgelege im Mittel 5,35±0,71 Eier, Ersatzgelege: 4,68±0,85). Der Bruterfolg war unabhängig von der Lage, der Höhe und der Verborgenheit des Nestes. Die mittlere Überlebensrate eines Nestes zwischen Bebrütung des Geleges und Ausfliegen der Jungen betrug 0,365. Dieser niedrige Bruterfolg wurde hauptsächlich durch Nesträuber verursacht. In Südfrankreich ist die Art aber vor allem durch die zunehmende Verschließung der Bruthabitate infolge des Rückgangs des extensiven Weidebetriebs gefährdet.

     

A matter of timing: changes in the first date of arrival and last date of departure of Australian migratory birds

Although there is substantial evidence that Northern Hemisphere species have responded to climatic change over the last few decades, there is little documented evidence that Southern Hemisphere species have responded in the same way. Here, we report that Australian migratory birds have undergone changes in the first arrival date (FAD) and last date of departure (LDD) of a similar magnitude as species from the Northern Hemisphere. We compiled data on arrival and departure of migratory birds in south‐east Australia since 1960 from the published literature, Bird Observer Reports, and personal observations from bird watchers. Data on the FAD for 24 species and the LDD for 12 species were analyzed. Sixteen species were short‐ to middle‐distance species arriving at their breeding grounds, seven were long‐distance migrants arriving at their nonbreeding grounds, and one was a middle‐distance migrant also arriving at its nonbreeding ground. For 12 species, we gathered data from more than one location, enabling us to assess the consistency of intraspecific trends at different locations. Regressions of climate variables against year show that across south‐east Australia average annual maximum and minimum temperatures have increased by 0.17°C and 0.13°C decade^?1 since 1960, respectively. Over this period there has been an average advance in arrival of 3.5 days decade^?1; 16 of the 45 time‐series (representing 12 of the 24 species studied) showed a significant trend toward earlier arrival, while only one time‐series showed a significant delay. Conversely, there has been an average delay in departure of 5.1 days decade^?1; four of the 21 departure time‐series (four species) showed a significant trend toward later departure, while one species showed a significant trend toward earlier departure. However, differences emerge between the arrival and departure of short‐ to middle‐distance species visiting south‐east Australia to breed compared with long‐distance species that spend their nonbreeding period here. On average, short‐ to middle‐distance migrants have arrived at their breeding grounds 3.1 days decade^?1 earlier and delayed departure by 8.1 days decade^?1, thus extending the time spent in their breeding grounds by ～11 days decade^?1. The average advance in arrival at the nonbreeding grounds of long‐distance migrants is 6.8 days decade^?1. These species, however, have also advanced departure by an average of 6.9 days decade^?1. Hence, the length of stay has not changed but rather, the timing of events has advanced. The patterns of change in FAD and LDD of Australian migratory birds are of a similar magnitude to changes undergone by Northern Hemisphere species, and add further evidence that the modest warming experienced over the past few decades has already had significant biological impacts on a global scale.     

Migration, wintering and breeding of a lesser spotted eagle ( Aquila pomarina) from Slovakia tracked by satellite

In northern Slovakia an adult male Lesser Spotted Eagle (Aquila pomarina) occupied the same nest site for 11 years running (1992–2002), where it was ringed and fitted with two satellite transmitters. In six of these years it successfully reared a young. In 1994 and 2000–2002 its behaviour during migration could be followed in detail by means of satellite telemetry. The eagle took the known route for this species to South Africa. In 2001, it spent 43% of the year at its breeding site, 33% in its winter quarters, the remaining 24% being spent on migration. In three cases the autumn migration took 40, 48 and 61 days respectively. In two cases the spring migration took 49 days. All five recorded autumn and spring migrations averaged a daily flight distance of 178 km. In spring the daily flight distance was in general slightly greater than in autumn. The longest was recorded from 30 March to 2 April 2001, between Uganda and the Red Sea, during which the bird covered a total of 1,650 km, averaging 412 km per day. In 2001, the spring migration from the wintering grounds was 2 weeks later than in 2002. The wintering grounds, where in 2 years the bird spent around 3.5 months, covering at least 1,666 and 2,269 km, respectively, comprised a large part of Zimbabwe together with the Kruger National Park in South Africa and neighbouring parts of Mozambique. The annual journeys flown, including movements around the wintering grounds, amounted in 2000-2001 to at least 20,396 km and in 2001-2002 to 19,041 km. Except during its crossing of the Sahara, the eagle must have taken food on nearly all its days of migration.