THE EFFECT OF AGE ON THE BREEDING BIOLOGY OF THE KITTTWAKE RISSA TRIDACTYLA

1. From 1954 to 1956 inclusive, the biology of individual marked Kittiwakes was studied at North Shields, Northumberland.
2. It was concluded that older Kittiwakes reacted to the breeding stimulus earlier, more intensively and with greater success than younger breeding birds.
3. Birds with previous breeding experience returned to the colony before birds breeding for the first time and these before non-breeders.
4. Before breeding started, birds which had bred previously spent more of their time at the colony than those about to breed for the first time.
5. Birds breeding for at least the second time laid the first egg 7·5 days earlier than those breeding for the first time.
6. Breeding started one day later for every four days the return to the colony was postponed.
7. Older breeding birds showed greater nest-site tenacity, laid larger clutches and had greater breeding success than younger birds.
8. The chicks in broods of two (but not of one) increased in weight more rapidly where the parents had previous experience.
9. Breeding Kittiwakes showed strong colony tenacity, but 24% of the marked non-breeding birds were subsequently seen in other colonies.
10. Over half the birds retained the same mate as in the previous year.     

Islands in a desert: breeding ecology of the African Reed Warbler Acrocephalus baeticatus in Namibia

The continental African Reed Warbler Acrocephalus baeticatus, like its relative the Seychelles Warbler Acrocephalus sechellensis, breeds in isolated patches. We studied the mating system of the African Reed Warbler to see whether this species, like the Seychelles Warbler, shows co-operative breeding. The African Reed Warbler is not polygynous. The majority breed monogamously (88%, n = 65), however in 12% of the territories three adult unrelated birds (mostly males) were observed participating in the brooding and feeding of nestlings, suggesting a polyandrous breeding system. Multilocus DNA fingerprinting revealed that the helping bird was unrelated to the pair birds. The percentage of nests with helpers was low compared to rates found in the Seychelles Warbler or Henderson Reed Warbler Acrocephalus vaughani taiti. This could be due to the scarcity of potential helpers or to the fact that, although limited, birds still had the opportunity to disperse within a meta-population structure in search of vacant territories. The presence of helpers was associated with increased hatching success due to lower predation rates, but not with increased fledging success. Another possible benefit of helping behaviour in this species could be improved predator detection and mobbing. Nest predation was high and warblers tended to build their nests in the highest, most dense reed patches available in their territory. There was no relation between habitat quality, measured as insect food availability, and the occurrence of helpers.     

Changes in the breeding avifauna of Israel during 2003–2016

Based on information obtained from publications, online material and experienced birdwatchers we describe changes in the breeding avifauna of Israel between 2003 and 2016. We provide details on nine species that were found breeding in Israel during this period for the first time (Common Shelduck, Great Cormorant, Black-winged Kite, Caspian Tern, White-cheeked Tern, Common Wood Pigeon, Black Bush Robin, Basra Reed Warbler, Chiffchaff); two species that were found breeding in Israel after they were not documented breeding for more than 50 years (Great Crested Grebe, Pallid Scops Owl), one species that significantly extended its breeding range in Israel (Striated Heron), and two exotic species that have recently established populations in Israel (Monk Parakeet, Vinous-breasted Starling). This brings the number of bird species breeding in Israel in 2016 to 220. We also report here that out of six new breeding species reported in 2003, three species established breeding populations in Israel, while the other species did not continue to breed in Israel regularly.     

Spring migratory routes of eight trans-Saharan passerines through the central and western Mediterranean; results from a network of insular and coastal ringing sites

Detailed information on spring migration routes of songbirds across the Mediterranean is still scanty. Results are presented here from a study on the occurrence of eight Palaearctic-African migrants across the western and central Mediterranean based on ringing data collected during the Progetto Piccole Isole, a co-ordinated project based on standardized mist netting at 21 islands and coastal stations. The species were Melodious Warbler Hippolais polyglotta , Icterine Warbler Hippolais icterina, Bonelli's Warbler Phylloscopus bonelli , Wood Warbler Phylloscopus sibilatrix , Pied Flycatcher Ficedula hypoleuca , Collared Flycatcher Ficedula albicollis , Red-backed Shrike Lanius collurio and Woodchat Shrike Lanius senator . Their capture frequencies were expressed as the frequency of each species relative to the total number of migrants ringed at each station in order to correct for differences in capture effort between stations. For most species, the detailed, quantitative results confirmed the scanty information available so far, whereas in the case of Melodious Warbler and Bonelli's Warbler, evidence of undescribed and unexpected migration routes was found. These results suggest that standardized mist netting provides an important method for studying the migratory routes of small birds, in particular for those species which are not frequently ringed in their breeding and wintering grounds.     

THE MAIN VICISSITUDES OF THE EUROPEAN AVIFAUNA SINCE THE PLIOCENE

.1. Recent knowledge of the Pleistocene and subsequent ecological changes is summarized. Four glaciations are recognized, each with more than one maximum. The interglacials were all at least as warm as the present day.
2. A map shows the vegetation belts of Europe and the probable limits of permanent sea-ice at the height of the Last Glaciation, about 70,000 years ago. There is reason to believe that the main features of the vegetation-map would apply also to the height of the other glaciations.
3. The avian fossil data are discussed and for the most part of necessity rejected for the present purpose.
4. The main inferences drawn of bird distribution at a glacial maximum are that ( a ) a rich avifauna occupied the treeless (grassy) loess-tundra on the southern edge of the ice, ( b ) practically no arboreal birds could live north of the Pyrenees, the Alps and the Black Sea except in a strip across central Russia, ( c ) the birds of deciduous woodland were confined to part of the three Mediterranean peninsulas, ( d ) "Mediterranean" species were practically expelled from Europe.
5. This implies that the populations of coniferous forest must have been reduced to about one-third of their interglacial extent in Europe and those of deciduous woodlands to one-tenth. Most of the sea-bird species probably suffered less severe fluctuations in numbers, but underwent north-and-south changes in breeding range.
6. The post-glacial recovery of the climate has not been uninterrupted, so that in the last 80,000 years there have probably been only about 8000 during which there have been any arboreal birds north of Germany.
7. The implications of the changes on the details of the migration system are discussed.     

BREEDING OF THE FULMAR FULMARUS GLACIALIS

.1. A study of individually marked Fulmars during three seasons has shown that both sexes can breed in successive years. The evidence for the theory of intermittent breeding is examined and definitions are given of the various categories of birds which compose the population during the breeding season. It is suggested that the supposed non-breeding adults which are seen, often in moult, in July are failed-breeders which have lost their egg or nestling.
2. No marked individual changed its nest-site between years, although the number and identity of sites occupied each July varied considerably.
3. No changes of mate occurred among the six marked pairs which nested in two consecutive years.
4. There is some evidence that both parents remain near the colony during the week before and after hatching.
5. Analysis of the 90 known sites of a colony subject to avian but not wild mammalian predation has revealed a wide range of habitat selection and a strong tendency toward close concentration of nests.
6. There is some evidence that the breeding season, as measured by date of hatching, varies from year to year.     

Geolocator reveals migratory and winter movements of a Prothonotary Warbler

Prothonotary Warblers (Protonotaria citrea) are Nearctic‐Neotropic migrants that have experienced declining populations over the past 50 yr. Determining their migration routes and wintering areas are critical steps in identifying habitats used by species and populations of conservation concern. We captured a male Prothonotary Warbler on its breeding territory in Louisiana in June 2013 and attached a geolocator. We recaptured this male in March 2014 and analysis of the geolocator data revealed that the male traveled an estimated 7950 km through seven countries. Fall migration was characterized by movements south into Central America on 13 August 2014, then east to the Greater Antilles for about 1 mo, followed by a second movement south to Panama or Colombia on 15 November 2014 where the male remained for the rest of the winter. Spring migration occurred rapidly, with the bird leaving its southern wintering area on 4 March 2014 and returning to its breeding territory on 23 March 2014. The movements of this male Prothonotary Warbler add to accumulating evidence that many migrant birds exhibit either prolonged stopover behavior or secondary migratory movements. Factors contributing to prolonged stopover behavior or additional migratory movements of the Prothonotary Warbler in our study warrant further investigation.     

近10年秦皇岛两种鸟类春季迁徙时间变化的差异性

气候变化对鸟类迁徙时间的影响是目前生态学研究的热点问题.本文利用鸟类环志的方法分析了2010至2019年河北秦皇岛两种鸟类春季迁徙时间变化趋势及其差异性,并进一步探讨了差异性的原因.选择环志数量较多的食虫鸟黄眉柳莺(Phylloscopus inornatus)和食谷鸟灰头鹀(Emberiza spodocephala...     

Biometry and phenology of two sibling Phylloscopus warblers on their circum-Mediterranean migrations

The Mediterranean Sea is known as an ecological barrier for numerous migratory birds flying from European breeding grounds to African wintering sites. Birds generally avoid migration over open sea and fly over land. In the Mediterranean Basin, few land bridges or bottlenecks for migratory birds exist. The narrowest are at the western and eastern extremes: the Strait of Gibraltar and Israel. Comparative studies between these locations are extremely rare to date. Therefore, in order to elucidate the differences between the two flyways, we compared data collected simultaneously for two sister leaf warbler species, the Bonelli’s Warbler complex, Phylloscopus bonelli and Phylloscopus orientalis, at ringing stations in the western Mediterranean Basin Gibraltar, and the eastern Eilat, Israel. Data on biometrics and passage dates of individuals trapped at Gibraltar and Eilat were used, and it was found that mean arrival date of Western Bonelli’s Warblers at Gibraltar was 15 days later than Eastern Bonelli’s Warblers at Eilat. Furthermore, Western Bonelli’s Warblers had shorter wings than Eastern Bonelli’s Warblers. On the other hand, birds in Eilat were in poorer body condition than individuals in Gibraltar. The comparison between geographically distant stop-over sites contributes to furthering our understanding of the development of migration strategies across ecological barriers in sibling species. Our study showed that populations that breed in southwestern Europe migrate through Gibraltar and winter in West Africa are able to accomplish migration in comparatively good body condition. This is in contrast to those that winter in East Africa, migrate through Israel and have to endure the combined challenge of crossing the Sahel, Sahara and Sinai deserts before reaching their breeding grounds across southeast Europe and southwest Asia. Hence, the discrepancies described between the western and the eastern flyway suggest that individuals in the west, in general, migrate shorter distances, have a physiologically less demanding crossing of the North African deserts and appear to stage before their crossing the Strait of Gibraltar, a privilege unavailable to the migrants of the eastern flyway.     

Further perspectives on the breeding distribution of migratory birds: South American austral migrant flycatchers

1. Patterns of distribution of breeding austral migrant tyrant-flycatchers in temperate South America were quantified and analysed in conjunction with a variety of ecological, biogeographical and climatic variables.
2. The pattern of proportion of migratory to total breeding tyrannids was most strongly associated with latitude and two temperature variables, mean temperature of the coldest month and relative annual range of temperature.
3. The strong associations of latitude and temperature with percentage of migrants are consistent with the results of most similar investigations of the breeding distributions of migratory birds, both for migrants breeding in North America and in Europe, but contradict the hypothesis that habitat complexity plays a major role in structuring the proportion of migrants in communities of breeding birds.
4. The consistency of results among studies of migrants on different continents suggests that temperature and latitude, presumably a surrogate for one or more climatic variables, are globally significant factors in the breeding distributions of migratory birds.
5. The results for austral migrant flycatchers are consistent with the hypothesis that the prevalence of migration at any particular locality is ultimately dependent on the abundance of resources in the breeding season and the severity of the winter season, or on the difference in resource levels between summer and winter.     

Is there a connection between weather at departure sites,onset of migration and timing of soaring‐bird autumn migration in Israel?

Aims Different aspects of soaring‐bird migration are influenced by weather. However, the relationship between weather and the onset of soaring‐bird migration, particularly in autumn, is not clear. Although long‐term migration counts are often unavailable near the breeding areas of many soaring birds in the western Palaearctic, soaring‐bird migration has been systematically monitored in Israel, a region where populations from large geographical areas converge. This study tests several fundamental hypotheses regarding the onset of migration and explores the connection between weather, migration onset and arrival at a distant site. Location Globally gridded meteorological data from the breeding areas in north‐eastern Europe were used as predictive variables in relation to the arrival of soaring migrants in Israel. Methods Inverse modelling was used to study the temporal and spatial influence of weather on initiation of migration based on autumn soaring‐bird migration counts in Israel. Numerous combinations of migration duration and temporal influence of meteorological variables (temperature, sea‐level pressure and precipitable water) were tested with different models for meteorological sensitivity. Results The day of arrival in Israel of white storks, honey buzzards, Levant sparrowhawks and lesser spotted eagles was significantly and strongly related to meteorological conditions in the breeding area days or even weeks before arrival in Israel. The cumulative number of days or cumulative value above or below a meteorological threshold performed significantly better than other models tested. Models provided reliable estimates of migration duration for each species. Main conclusions The meteorological triggers of migration at the breeding grounds differed between species and were related to deteriorating living conditions and deteriorating migratory flight conditions. Soaring birds are sensitive to meteorological triggers at the same period every year and their temporal response to weather appears to be constrained by their annual routine.     

OBSERVATIONS ON THE BEHAVIOUR OF BIRDS IN SOUTHERN RHODESIA

Maclean, G. L. 1974. The breeding biology of the Rufouseared Warbler and its bearing on the genus Prinia. Ostrich 45: 9–14.

The Rufouseared Warbler Prinia pectoralis, a common species of the Kalahari scrub, nests after rain at any time of the year. Nest construction and nest sites are described. The clutch is normally three or four eggs. Incubation takes 12 to 13 days and the nestling period is 11 to 13 days. Data suggest that the Rufouseared Warbler is not a member of the genus Priniu, the generic position it currently occupies.     

Postbreeding elevational movements of western songbirds in Northern California and Southern Oregon

Migratory species employ a variety of strategies to meet energetic demands of postbreeding molt. As such, at least a few species of western Neotropical migrants are known to undergo short‐distance upslope movements to locations where adults molt body and flight feathers (altitudinal molt migration). Given inherent difficulties in measuring subtle movements of birds occurring in western mountains, we believe that altitudinal molt migration may be a common yet poorly documented phenomenon. To examine prevalence of altitudinal molt migration, we used 29 years of bird capture data in a series of linear mixed‐effect models for nine commonly captured species that breed in northern California and southern Oregon. Candidate models were formulated a priori to examine whether elevation and distance from the coast can be used to predict abundance of breeding and molting birds. Our results suggest that long‐distance migrants such as Orange‐crowned Warbler (Oreothlypis celata) moved higher in elevation and Audubon's Warbler (Setophaga coronata) moved farther inland to molt after breeding. Conversely, for resident and short‐distance migrants, we found evidence that birds either remained on the breeding grounds until they finished molting, such as Song Sparrow (Melospiza melodia) or made small downslope movements, such as American Robin (Turdus migratorius). We conclude that altitudinal molt migration may be a common, variable, and complex behavior among western songbird communities and is related to other aspects of a species’ natural history, such as migratory strategy.     

THE SOCIAL BEHAVIOUR OF THE WHITE WAGTAIL MOTACILLA ALBA ALBA WINTERING IN ISRAEL

White Wagtails Motacilla alba wintering in Israel are partly territorial, mostly around human habitations, and partly live in flocks around temporary food sources. Individual birds may spend part of the season (or the day) in the territory and the other part with a flock. Experiments with artificial distribution of food, in a natural habitat, brought about a change from flocking to territorial behaviour. Preliminary observations suggest that in the natural situation the pattern of food distribution may be the proximate factor which regulates the birds' behaviour, by determining whether they have to fight for their food. Pairs are formed on many territories, and may last for long or short periods. Pair formation is initiated by females, who when seeking food appease the territorial males and are able to stay with them on their territories. Females also manifest territorial behaviour. Although pairing in winter territories is similar, in the behaviour involved, to sexual pairing, it is very unlikely that winter pairing continues into, or influences, pairing for breeding. It is suggested that the function of winter pair formation is that it allows two birds to exploit one territory, and that the main advantage is to the female which is the subordinate bird of the pair. This kind of pair-formation may be analogous to non-breeding group territories reported in some other birds.     

Intermittent breeding in the short-tailed shearwater Puffinus tenuirostris

1.  At one colony of short-tailed shearwaters in Bass Strait, Australia, all birds breeding have been recorded individually each year for over 50 years. Among individuals known to be alive and to have bred before, 14% of each sex were not present at their breeding colony, on average, in any one year.
2.  A further 15% of males and 13% of females (a significant difference), known to have bred before, were present but not associated with an egg in any one year.
3.  Intermittent breeding was associated with pair bond breakdown and with a reduced ability to raise offspring, even when years of absence were allowed for.
4.  The frequency of attendance, laying and successful rearing of progeny to fledging increased with age in the early years of breeding. However, this was followed by a decrease, except in the case of laying frequency, which continued to increase throughout life.
5.  Our analysis indicated that intermittent breeding in short-tailed shearwaters did not result from individuals implementing trade-offs between the effort required for breeding success and their breeding life span. Rather, we suggest that individuals of higher quality are able to breed more frequently than others without any compensatory reduction in either their annual breeding success or their overall breeding life span.     

Prolonged copulation, sperm reserves and sperm competition in the Aquatic Warbler Acrocephalus paludicola

The Aquatic Warbler Acrocephalus paludicola has a quasi-promiscuous mating system with high levels of multiple paternity and, thus, intense sperm competition. The duration of copulation in the Aquatic Warbler is unusually long. In hand-reared, captive birds the duration of mounting was 23.7 ± 11.8 min (mean ± s.d.). On average, six cloacal contacts (inseminations) occurred during each copulation. Between inseminations the male remained in contact with the female, either on top of or directly behind her. Protracted copulation may be a form of contact mate guarding, a behaviour not previously recorded in birds. Copulation was most frequent during the evening and early morning. Male Aquatic Warblers also exhibit extreme morphological adaptations of their reproductive system compared with other Acrocephalus species and other birds: their testes, cloacal protuberance and seminal glomera (which contain 198 × 10⁶ spermatozoa) are all relatively large. Frequent insemination during protracted copulation and contact mate guarding may be alternatives to paternity guarding found in other birds.     

Clutch size of passerines at mid-latitudes: the possible effect of competition with migrants

The clutch sizes of the passerines of Israel and the Cape Province, South Africa, which lie at similar latitudinal range, were compared. Mean clutch sizes in Israel and the Cape Province are 4.09 and 2.87, respectively. Mean clutch size of Israeli migrants is larger than that of residents (4.45 and 3.93, respectively), but no such difference exists in the Cape Province.
It is suggested that the larger clutch size in Israel is a result of two factors: (1) the higher proportion of wintering birds in Israel in comparison with the Cape Province and the presence of many transients there which may compete with resident birds and cause high winter mortality among them and (2) a higher proportion of migrants in the Israel avifauna, which suffer heavy losses during their trans-Saharan migration in comparison with Cape Province migrants, which travel shorter routes. The resulting reduced competition for food during the breeding season in Israel enables passerines there to lay larger clutches as predicted by Ashmole (1963) and Ricklefs (1980).     

Extreme genetic similarity does not predict non‐breeding distribution of two closely related warblers

Detailed knowledge of migratory connectivity can facilitate effective conservation of Neotropical migrants by helping biologists understand where and when populations may be most limited. We studied the migratory behavior and non‐breeding distribution of two closely related species of conservation concern, the Golden‐winged Warbler (Vermivora chrysoptera) and Blue‐winged Warbler (Vermivora cyanoptera). Although both species have undergone dynamic range shifts and population changes attributed to habitat loss and social interactions promoting competition and hybridization, full life‐cycle conservation planning has been limited by a lack of information about their non‐breeding ecology. Because recent work has demonstrated that the two species are nearly identical genetically, we predicted that individuals from a single breeding population would have similar migratory timing and overwintering locations. In 2015, we placed light‐level geolocators on 25 males of both species and hybrids in an area of breeding sympatry at the Fort Drum Military Installation in Jefferson and Lewis counties, New York. Despite extreme genetic similarity, non‐breeding locations and duration of migration differed among genotypes. Golden‐winged Warblers (N = 2) overwintered > 1900 km southeast of the nearest Blue‐winged Warbler (N = 3) and spent nearly twice as many days in migration; hybrids (N = 2) had intermediate wintering distributions and migratory timing. Spring migration departure dates were staggered based on distance from the breeding area, and all birds arrived at the breeding site within 8 days of each other. Our results show that Golden‐winged Warblers and Blue‐winged Warblers in our study area retain species‐specific non‐breeding locations despite extreme genetic similarity, and suggest that non‐breeding locations and migratory timing vary along a genetic gradient. If the migratory period is limiting for these species, our results also suggest that Golden‐winged Warblers in our study population may be more vulnerable to population decline than Blue‐winged Warblers because they spend almost twice as many days migrating.     

POLYGYNY AND BREEDING ECOLOGY OF THE CETTI'S WARBLER CETTIA CETTI

Male Cetti's Warblers bred simultaneously with up to three females. Harem size was correlated with size of male but not of his territory. Males occupied large usually exclusive ranges and devoted much time to patrolling and singing often far from their nests. Incubation was solely by the female who also provided most to all of the food for the young. Incubation and fledging periods were prolonged compared with similar sized birds but first nests were unusually successful. Polygynously mated females laid larger clutches than monogamous ones. Males with fewer females took a greater share of feeding but chick growth and survival were not impaired by polygyny, nor did foods brought to the young differ accordingly. The existence of this unusual breeding system is discussed with emphasis on the co-evolution of sexual dimorphism and non-equal sex ratios resulting from malemale competition. It is postulated that the linear dispersion of its habitat may especially have favoured operation of the Verner-Orians polygyny model in the evolutionary history of the Cetti's Warbler.