Precise direct tracking and remote sensing reveal the use of forest islands as roost sites by Purple Martins during migration

Direct tracking methods in combination with remote sensing data allow examination of habitat use by birds during migration. Species that roost communally during migration, such as some swallows, form large aggregations that can attract both avian and terrestrial predators. However, the extent to which they might use patchy habitats that could reduce predation risk during migration is unknown. We tested the hypothesis that Purple Martins (Progne subis) use forest islands (patches of suitable forest habitat surrounded by unsuitable habitat) as roost sites during migration between breeding sites in North America and overwintering sites in South America. We used high‐precision (< 10 m), archival GPS units deployed and retrieved during the 2015 and 2016 breeding seasons, respectively, at 12 colonies located across eastern North America. We found that Purple Martins roosted in forest islands more often than expected based on availability during both spring and fall migration. Despite an apparent association with urban habitats by Purple Martins based on observational and radar data in North America during the fall, the roost locations we identified during spring and fall migration were not more closely associated with urban areas than random locations. The use of forest islands during both spring and fall migration suggest that Purple Martins may use these habitats to reduce predation risk during migration. Our results suggest that some species of birds may use similar habitats as stopover sites during migration and that patches of forest habitat may be important conservation targets for Purple Martins and other species. Identifying habitat use during migration represents an important advance in support of full annual‐cycle conservation of Purple Martins and other migratory species with declining populations.     

ESTABLISHMENT OF WEIGHT HIERARCHIES IN THE BROODS OF HOUSE MARTINS DELICHON URBICA

Nestling birds may differ in size and weight on the first day a clutch is fully hatched, mainly because eggs within clutches hatch over a period of several days. This asynchronous pattern of hatching is usually thought to facilitate brood reduction when the food supply is unpredictably restricted. The purpose of the study reported here was to examine the contribution of egg-weight, clutch-size, hatching spread, food supply and season to weight differences in newly hatched broods of the House Martin. At laying, heavy eggs had a greater moisture and dry weight content than light eggs and immediately before hatching there was a correlation between initial egg-weight and the dry weight of embryo and yolk. Heavier clutches also tended to give rise to heavier hatchlings. There was, however, no correlation of fresh egg-weight with the dry weight of embryos alone and the relative dry weight of embryos in a clutch was dependent on laying sequence. Hatching spread (the number of days between the emergence from the egg of the first and the last hatchling of the clutch) was 0.75 ± 0.46 days for clutches of two and increased with the size of the clutch up to 1.80 ± 0.79 days for clutches of five. When food was scarce during laying, hatching spread was greater. Weight difference in newly hatched broods was correlated with hatching spread and moreover in multivariate analysis was also correlated with periods of food scarcity during laying. It was concluded that all examples of weight hierarchies among hatchlings should not be considered adaptive; in some cases they may be imposed by food scarcity. This can lead to mortality of the runs even if food is plentiful. When the weight hierarchy is not adversely accentuated by food scarcity it may function as previously suggested, to allow brood reduction. Alternatively, particularly among House Martins, it may spread out the peak food needs of individual nestlings thereby spreading the demand on the adults.     

BREEDING BIOLOGY OF HOUSE MARTINS DELICHON URBICA IN RELATION TO AERIAL INSECT ABUNDANCE

The breeding biology of House Martins nesting in artificial boxes was examined in relation to aerial insect abundance and weather. The insect food supply was continuously monitored with a suction-trap at 40 ft above ground level. Aerial insect abundance started to rise from the winter level in April and reached a high stable state in June. Insects remained abundant until September; the subsequent decline continued at least until the end of October. The size of first clutches (mean size 3.87) was correlated with the abundance of aphids in spring, though not with temperature. It is suggested that this was an adaptive response because high food levels in May were associated with high levels in the main nesting period. Clutch-size declined through the season but was not matched by changes in food abundance. Second clutches (mean size 2–95) were most frequent following a high food level in June. No correlation was found between egg-weight and preceding food conditions, nor with season, clutch-size or order of laying within clutches. If food was scarce on the day of laying of the first egg, these clutches suffered a suspension of laying of subsequent eggs. Some of the young in these nests showed a reduced growth rate. The duration of incubation (mean 14.6 ± 1.1 days) was not apparently correlated with food abundance, however it must have been potentially extended by extreme shortages because incubation duties were neglected at such times. Infertility was probably the main cause of hatching failure (14.2%). A model was used to predict the date of onset of laying. It was based on the assumption that nestling tissue was produced with the same energetic efficiency as eggs. The model indicated that House Martins could collect enough food to lay eggs earlier than the observed date in most years. The high probability of food shortage before the laying period, however, appeared to discourage laying at this time. The observed onset of laying coincided with the appearance of aphids in the air, probably because they comprised an abundant and stable food source for egg formation. Breeding generally occurred in the period of highest food abundance. Pairs rearing only a single brood each year did so in July when food levels were highest. The growth of first brood nestlings was more closely associated with food levels than any other factor investigated, while in second broods, rainfall was found to have the greatest influence. The total variance in growth explained by environmental factors in the first broods (41%) was greater than in second broods (22%). This relative independence of second broods from adverse environments probably arose from more abundant food and the feeding of some of these broods by the young of first broods. An exceptionally late brood showed an extended nestling period indicating deteriorating conditions later in the breeding season. It is proposed that the spread of laying may reflect differences in the feeding efficiency of nesting House Martins, because the growth of two early first broods was more rapid at given food levels than two late broods. Laying patterns conformed to a distribution based on a progressive threshold mechanism. The more efficient pairs may be able to attain breeding condition and lay at low levels of food abundance, and hence breed earlier in the season. Subsequent layings are facilitated by the rise in food levels in early summer. Mortality within the nest was low (5.8%) and associated with food shortage. Nestling periods (mean 30.6 ± 2.3 days) were not shown to be correlated with food abundance; they were more dependent on brood-size. Recruitment into House Martin populations is thus widely influenced by food supply, particularly through an influence on clutch-size, the occurrence of second clutches and nestling mortality.     

异华鲮属鱼类口唇及其相关结构形态学的研究

异华鲮属鱼类为我国特有的小型流水性鲤科鱼类,分布于长江和珠江中下游水系,具有独特的口唇及其相关结构,隶属于野鲮亚科。多样化的口唇及其相关结构是野鲮亚科与鲤科其他类群的分歧所在,也是其属级单元分类的主要依据。但是野鲮亚科鱼类口唇及其相关结构的多态现象成为其类群相关关系分析的难题。因此,异华鲮属鱼类以往被认为与不同的类种有密切的关系。本文和比较形态学方法,对异华鲮属鱼类口唇及其相关结构的特征进行了研究     

MOULT OF THE PURPLE SANDPIPER CALIDRIS MARITIMA IN ICELAND

The autumn moult pattern of adult Purple Sandpipers Calidris maritima in Iceland is described. The duration of the moult was estimated to be c. 5½-7 weeks (c. 40–50 days). Females generally started moult before males and moult did not appear to overlap breeding. Information from other areas is reviewed. A mechanism by which the duration of moult is shortened amongst various species is by an increase in the number of feathers growing concurrently during the moult. Likely reasons for the placing of the moult in the annual cycle of the Purple Sandpiper are discussed, and appear to be related to the exceptionally northerly wintering distribution of the species.     

THE BURROW-EXCAVATION PHASE IN THE BREEDING CYCLE OF THE SAND MARTIN RIPARIA RIPARIA

Observations were carried out at a Sand Martin colony in a working sand-pit, where fresh burrows have to be dug each year. Sand Martins arrive at the breeding pit from migration unpaired, and their social organization is then at its lowest. Burrow excavation occurs only as the climax to a form of group display. Digging is communal in character, and the number of holes dug is roughly equal to the number of individual birds present. The mounting excitement and mutual stimulation of the display period induces a climax at which the birds begin to build nests and lay. This period of display produces close synchronization which seems to be a necessary condition for the communal behaviour of the birds during the rest of the breeding cycle.     

Aggression in shorebirds in relation to flock density and composition

The aggressive interactions of Turnstones and Purple Sandpipers feeding in wintering mixed-species wader flocks could be classified into those involving food and those involving space. All observed interspecific encounters were of short duration and were initiated and won by the larger species; the majority did not involve food and were resolved by low-intensity displays. Intraspecific interactions (a greater proportion of which involved food) were also resolved quickly and were usually won by the initiator. Space-related encounters between conspecifics were more likely to be resolved than food-related encounters just by threat displays. Aggression rates increased with flock densities. However, the increase in aggression with density was dependent on the species composition of the flock: both Turnstones and Purple Sandpipers were more likely to be involved in fights (both over food and over space) with conspecifics than with other species, indicating that the aggression costs of flocking were less in mixed-species flocks.     

两种状态细菌视紫红质光循环中间产物与pH的关系

本文主要用微机控制的毫秒级闪光动力学光谱仪研究含三体细菌视紫红质(Bacteriorhodopsin,简称BR)的紫膜碎片和含单体BR的DMPC(dimyristoyl-Phosphatidyl-choline)脂质囊泡在不同pH条件下光循环中间产物M_(412)和O_(640)的变化,研究结果表明:BR单体与其三体状态相比,BR单体的光循环中间产物M_(412)的产量受介质pH变化的影响较大,其慢衰减成份的衰减比三体BR慢3—10倍.说明单体BR的结构状态较易受PH影响,单体BR光循环中间产物O_(640)随pH变化的趋势与三体BR的有很大区别,可能是由于不同状态的BR受pH的影响,但其具有不同的构型,导致光循环途径的变化.     

NOTES ON THE BREEDING BIOLOGY OF THE AFRICAN SPOONBILL PLATALEA ALBA

Silbernagl, H. P. 1982. Seasonal and spatial distribution of the American Purple Gallinule in South Africa. Ostrich 53:236-240.

The American Purple Gallinule Porphyrula martinica has been recorded 21 times in the southwestern Cape Province of South Africa. Nearly all records fall in the period 22 April to 2 July and nearly all birds were juveniles. The majority of dated records for which weather data are available appear to be of birds starting their northward migration in Buenos Aires Province, Argentina, or Uruguay and caught by strong westerly winds which carry them downwind to South Africa in about five days. Most birds arrive in South Africa in an exhausted condition and markedly below normal weight. Thus it is unlikely that the American Purple Gallinule will establish a breeding population in Africa.     

Diet breadth and overlap in three sympatric aerial insectivorous birds at the same location

Capsule We found significant differences in the composition and diversity of diet among House Martins, Barn Swallows and Swifts breeding in the same village in Poland.

Aims To evaluate the character and extent of diversity, specialization and overlap of diet between trophically similar nestlings of three species of aerial feeding birds breeding at the same location and differing considerably in foraging height.

Methods Diet was determined based on faecal analysis. Differences in composition and diversity of diet and food niche overlap were assessed through multivariate analysis of variance (manova), Shannon Diversity Index and the Pianka index. Diet specialization was measured by application of the Berger–Parker index of dominance.

Results manova indicated significant differences in diet composition among all three species. House Martins showed the most diverse diet, Swallows were intermediate and Swifts least diverse. Average body mass of all prey found in the diet of Swifts was nearly three times smaller than in Swallows and two times smaller than in House Martins.

Conclusion Our findings show that these three species consume the same types of insect prey, but they take different proportions, and hence biomass, of the major prey groups. House Martins had the widest niche and greatest overlap.     

Isotopic analysis of island House Martins Delichon urbica indicates marine provenance of nutrients

The presence of one of the largest colonies of House Martins in Europe on the small island of Stora Karlsö, Sweden, led us to investigate the source of their food by analysis of stable isotopes of carbon and nitrogen. Carbon isotopic values of House Martin nestlings were the same as those of Common Guillemot Uria aalge nestlings fed on marine fish, but differed from local Collared Flycatcher Ficedula albicollis nestlings fed on woodland insects. We infer that these House Martins fed their chicks almost exclusively on insects that had used nutrients derived from seabirds, indicating a dependence on the presence of a large seabird colony. We suggest by extension that some populations of island passerines of high conservation importance may also be dependent on nutrient subsidies from seabird colonies.     

CURRENT ADVANCES IN THE TAXONOMY OF POTHOS

The VI Intemaional Aroid Conferece was held at Kunming in Yunnan Province in southerm China be-tween June 26 and July l, 1995. The conference was well attended with 80 Chinese participants and 30 Partic-ipants from Hong Kong and 10 othe countries. These were India, Singapore, Thaiand, Japan, South Africa,Croatia, Switzerland, Germany, England and the United States.     

STUDIES OF THE PURPLE HERON,PART 3: EGG AND CHICK DEVELOPMENT

Tomlinson, D. N. S. 1975. Studies of the Purple Heron, Part 3: Egg and chick development. Ostrich 46:157-165. (Part 1, Ostrich 45:175-181; Part 2, Ostrich 45:209-223.)

The average clutch size of Ardea purpurea was found to be three eggs, with a mean incubation period of 26 days. Incubation begins immediately the first egg is laid with the result that there is a marked difference in chick size in individual nests. The optimum clutch size in terms of fledgling success, is four to a nest, although growth data from nests indicate that the fourth chick in a nest with four is not fed adequately, and the fifth chick in a nest with five dies of starvation.

In agreement with Junor's (1971) results on other herons, food expressed as a percentage of body weight per day was found to level off at 16% which was 225 g of food per bird (adult weight) per day.     

中国兜蕊兰属植物的研究

兜蕊兰属是一个仅６种的属,分布于克什米尔地区、喜马拉雅、中国和日本。本文从其分类和植物地理的研究和修订,此属在我国现知产５种,包括一个新种和一个新组合种,其中３种特产于我国,文中有国产５种的分种检索表和每个种的异名和地理分布。     

NOTES ON THE CAPRIMULGIDAE OF THE KAFUE BASIN

During 2002–2007, we assessed the status of the Purple Heron Ardea purpurea in Numidia, Algeria by surveying all the major wetlands in the region. We located six distinct breeding sites; four of these were not previously known. We also investigated nest site selection and determined the species’ reproductive success at Dakhla, a dunary pond during two successive years (2006 and 2007). The egg laying period was comparable to that reported for southern Europe (March-May) and a seasonal change of breeding success was recorded. A growth curve was derived for developing nestlings and the impact of an ectoparasite (mite) infestation upon nestling's growth was considered. We also examined 73 food boluses regurgitated by nestlings and identified 329 prey items. Fish, mainly Gambusia holbrookii and Cyprinus carpio, dominated by mass, whereas insects, mainly aquatic Coleopteran larvae and aeshnids (Odonata), were the most frequent prey (67.1%). Loss of habitat is identified as a major threat to the future of colonial herons in Algeria.     

THE MIGRATION PATTERNS OF THE PURPLE SANDPIPER CALIDRIS MARITIMA

Summers, R. W. 1994. The migration patterns of the Purple Sandpiper Calidris maritima. Ostrich 65: 167–173.

The Purple Sandpiper breeds largely in the Arctic, and winters (boreal season) on the rocky shores of the north Atlantic, further north than any other sandpiper. As the populations from Canada, Greenland, Iceland, Svalbard, Norway and Russia differ in wing and bill lengths it is possible to match measurements taken from breeding birds with samples of birds caught in winter. Ringing recoveries, especially from colour marked birds, have also helped to determine migration routes and wintering areas. Four populations move to the nearest ice-free coast. Two populations move south of the nearest ice-free coast, being replaced by larger birds from a more northerly population (“chain migration”). Only the north Canadian population is believed to migrate a long distance, “leap-frogging” other winter populations. These patterns are discussed in relation to theories for the migration patterns of waders.     

THE EFFECT OF DIFFERENT HOST PLANTS OF POTATO VIRUS C IN DETERMINING ITS TRANSMISSION BY APHIDS

A stock of potato virus C derived from Edgecote Purple potatoes in 1945 was not then transmitted by aphids, although more than 2000 aphids were used in conditions optimal for transmitting the serologically related potato virus Y. This stock of virus C has been propagated continuously since, by manual inoculation in a series of Nicotiana glutinosa and N. tabacum , and in 1955 it was transmitted by the aphid Myzus persicae (Sulz.): about one in twenty of the aphids transmitted it compared with one in two for potato virus Y.
Virus C derived from the Edgecote Purple potatoes in 1955 was not transmitted by aphids; both stocks of virus C produced only local lesions in Majestic potato leaves, and gave similar symptoms in tobacco.
When inoculated to Majestic potatoes and then returned to tobacco plants, potato virus C usually ceased to be aphid transmitted and did not recover this property in any of the subsequent subcultures.
Transmission from stock by aphids did not isolate a strain of virus C which was any more readily transmitted by aphids, indeed, for the first two or three subcultures, aphids usually transmitted more readily from plants inoculated manually. But the few isolates which remained aphid transmissible, after a second passage through potato, were rather readily transmitted.
These results suggest that the ability of a virus to be aphid transmitted is, at least in part, determined by the host plant in which it is multiplying, but the nature of the changes which determine this ability are unknown.     

PM-SP-LB多层膜中BR分子的有序定向排列

用垂直转移法在石英片上制成的PM—SP—LB多层膜的可见区吸收谱表明吸收峰峰位与成膜液一致,均在574nm左右,比PM水悬浮液的吸收峰位略有红移;稳态线二色性表明,除PM碎片平躺在多层膜平面内外,在提拉时的竖直方向存在BR的取向优势,优势率约为0.51左右;同时还表明,25mN/m条件下制备的PM—SP—LB多层膜中BR分子的视黄醛生色团的跃迁矩与膜平面法向所成的角接近于天然紫膜中的值。     

Seasonal, size- and age-related patterns in body-mass and composition of Purple Sandpipers Calidris maritima in Britain

The masses of 3229 Purple Sandpipers Calidris maritima from Britain were analysed for differences related to age, season and size. First-year birds were lighter by 2 g. There was only a slight increase in mass in mid-winter, in contrast to other waders wintering in Britain, suggesting that Purple Sandpipers are less at risk to cold weather and food shortages. Their winter fat reserves were low but their breast muscles were relatively larger than other small waders wintering in Britain. Their plumage was slightly heavier and their breast and belly feathers were longer. There was a large increase in mass in May by first-year and adult birds prior to migration. The 'long-billed' population showed a greater relative increase in May, compared with the 'short-billed' population, perhaps reflecting different migration distances.     

CONTRIBUTION OF THE CLASS CRYPTOPHYCEAE TO PHYTOPLANKTON STRUCTURE IN THE GERMAN BIGHT1

The class Cryptophyceae (Division Cryptophyta) contains ecologically relevant species, which are widespread in aquatic environments. However, classification, identification, and enumeration of cryptophytes are challenged by a morphology that must be usually examined with EM to permit species identification. The quantitative importance of this group has been revealed by HPLC data. But ecological information assessing the occurrence or seasonality of cryptophytes in the marine environment is still scarce. Molecular techniques allow for a refined assessment of taxonomically challenging taxa, such as the cryptophytes. In our laboratory, a Phylochip was developed to facilitate and refine the assessment of cryptophyte microalgae. Here, we present the results of an environmental study that took advantage of the Phylochip. The study was designed to elucidate the seasonality and contribution of cryptophytes to phytoplankton structure in the German Bight. The occurrence of cryptophytes in total plankton versus the picoplankton fraction was assessed with the Phylochip between the years 2004 and 2006. Our data indicate that cryptophytes are an important and constant contributor to phytoplankton structure of the German Bight, especially in the picoplankton fraction.