Movements,status, access to nectar,and spatial organisation of the tui

Abstract

Movements of tui (Prosthetnadera novaeseelandiae) breeding on Tiritiri Matangi Island were followed and related to changes in nectar access. The island has limited nectar sources and birds must move to gain access to nectar year round. All tui leave the island, although the extent and timing of movement varies for different individuals. Tui return for breeding but again the timing of the return varies for individuals. Nectar sources were typically concentrated in both time and space, and access was related to individual asymmetries such as sex, residential status and age. These same asymmetries also relate to the timing of individuals movements, and where individuals nest relative to nectar sources. At concentrated food sources, access was determined by an absolute social hierarchy. Although tui defend exclusive feeding territories, breeding territories are not exclusive and access to nectar is determined by distance to nest site. Such variability in spatial organisation is related to a continuum concept of social organisation.     

Differences in the diet of the male and female tui (Prosthemadera novaeseelandiae: Meliphagidae)

Abstract

Tui are shown to be highly nectarivorous but observations show differences in degree of importance between the three food categories; nectar, fruit and arthropods, according to season. Foraging observations were significantly different for male and female tui during spring and especially during autumn, with males taking more nectar and females taking more arthropods.     

Woodpigeon Columba palumbus movements in eastern England

Capsule Woodpigeons range over greater areas during winter than summer with winter dispersion greatest in the first two winters following fledging.

Aims To radiotrack Woodpigeons, to analyse the BTO ringing recoveries and to examine ranging behaviour.

Methods Movements of 19 adult and nine newly fledged Woodpigeons around a 1070-ha study site in eastern England were monitored by radiotracking. The BTO recovery data were analysed for birds ringed in arable areas of Britain during the period 1950 to 1999.

Results The mean 95% minimum convex polygons during the summer were 254 ha for adults and 294 ha for juveniles. These ranges increased to 628 ha for adults and 1283 ha for juveniles during winter. Although they left the study area over the winter, some radiotagged juveniles returned to their natal areas the following summer. Winter dispersion followed by a return to the natal area the following summer only occurred for the first two years of life.

Conclusion Although Woodpigeons are largely sedentary, the winter dispersion of juvenile birds will weaken any effect of localized winter shooting on the numbers of breeding birds in that area the following spring.     

Diet of young Great Bustards Otis tarda in Spain: sexual and seasonal differences

Capsule Arthropods are the most important diet component of Great Bustards Otis tarda in the first months of life.

Aims To determine the diet composition of young Great Bustards in Spain.

Methods The diet was estimated by stomach content analysis (n?=?49).

Results Stomach contents' dry weight consisted of 33% arthropods, 30% green plant material and 23% seeds. Gastroliths were only found in summer and autumn. The diet composition changed significantly between seasons. In summer, diet consisted mainly of arthropods (50%), with green plant material being the main component in winter (56%). Volume of stomach contents and mean size of ingested arthropods were higher in males than in females. Diet composition did not differ between sexes. In summer, ground-dwelling and plant-visiting arthropods such as Mantidae, Tenebrionidae and caterpillars were the most abundant. In winter, weeds, legumes and cultivated seeds were more frequent than arthropods. Cereal plants were the least consumed in all seasons, although Barley and Wheat seeds played an important role during winter and autumn.

Conclusion The results highlight the importance of arthropods and weeds as a fundamental component of the diet of young Great Bustards. Because previous studies show that arthropods and weeds are usually more abundant in extensive farming, we recommend the implementation of agri-environmental measures in Great Bustard breeding areas.     

Seasonal changes in a honeyeater assemblage in Banksia woodland near Perth,Western Australia

Abstract

Honeyeaters were the most numerous birds in banksia woodland near Perth, Western Australia, throughout the year. Numbers were greatest in a Banksia littoralis swamp, but only during those few months when it contained large amounts of nectar. In the surrounding woodland, numbers were lower but fairly constant during the year. This reflects the smaller amounts of nectar produced throughout the year, by the overlapping flowering patterns of several Banksia and Adenanthos species.

Large and medium-sized honeyeaters (wattlebirds and New Holland Honeyeaters) and flocking silvereyes dominated the swamp when it flowered. In contrast, small honeyeaters (spinebills and Brown Honeyeaters), many of whom were highly territorial residents, comprised the majority of the woodland assemblage throughout the year. These observations support a model based upon aggressive defence of rich nectar sources by the larger honeyeater species, and more efficient exploitation of dispersed flowers by smaller honeyeaters.     

The Olson Mound (39BF223) in Buffalo County,South Dakota

Abstract

A low, dome-shaped, earthern tumulus was excavated during the summer of 1957. The mound contained poorly preserved remains of a secondary burial in a shallow, sub-mound pit. Three individuals were represented in the burial.

Artifactual associations were sparse.They consisted of one simplestamped body sherd, 2 end scrapers,4 knives; 1 drill and 3 mealing stone fragments.

Similarities between this mound and other sites in the vicinity are discussed. An appendix contains the analysis of the identifiable skeletal material.     

Are nectar guide colour changes a reliable signal to pollinators that enhances reproductive success?

Background: Ageing and post-pollination changes in floral colour occur widely in flowering plants, but it remains an open question as to whether or not colour changes in nectar guides are associated with the quantity of floral rewards that ultimately influence pollinator visitations and reproductive success.

Aims: To examine whether nectar guide changes should be considered as a reliable signal to pollinators and to assess the effects of nectar guide changes on reproductive success.

Methods: We studied the process and adaptive value of colour changes in the nectar guides of Arnebia szechenyi whose flowers typically display conspicuous nectar guides at the onset of anthesis, after which they begin to fade, and disappear completely on the second day.

Results: Changes in nectar guide colour in A. szechenyi were intrinsic and age-dependent, although pollination somewhat accelerated the change. By the time that the nectar guides disappeared completely, floral rewards were reduced almost to zero. Artificial removal of nectar guides decreased both fruit set and pollen export. Flowers without nectar guides do not appear to increase the overall attractiveness of the plants.

Conclusions: Nectar guides and their changes represent reliable signals to pollinators and enhance both male and female reproductive success.     

Long-term population declines in Danish trans-Saharan migrant birds

Capsule Long-distance migrant birds show less favourable trends than sedentary/short-distance species.

Aims To use breeding bird surveys to contrast population trends amongst common species according to their migration pattern.

Methods Changes in abundance of 62 Danish breeding sedentary, short-distance (Europe/North Africa) or long-distance (trans-Saharan) migrants were described by fitting log linear regression models to point-count census data gathered during 1976–2005.

Results Trans-Saharan migrants declined by 1.3% per annum during this period, while short-distance migrants and sedentary species increased by 1.4% and 1.0% per annum, respectively. There were no significant decadal declines amongst species using different summer breeding habitats, except for wetlands, and there was no consistent variation in trends associated with wintering regions or habitats or diet.

Conclusions More information is urgently needed on diet, feeding ecology, habitat requirements, winter distribution and intra-African movements of the commoner European summer visitors to identify causes of the declines and highlight when in the annual cycle detrimental effects occur. Studies linking individuals on their breeding, staging and wintering grounds are especially needed. Danish trends resemble those from elsewhere in Europe, confirming that restoration to favourable conservation status requires inter-continental action to meet European and global targets to reduce or halt biodiversity loss.     

Understanding ontogenetic trajectories of indirect defence: ecological and anatomical constraints in the production of extrafloral nectaries

Background and Aims

Early ontogenetic stages of myrmecophytic plants are infrequently associated with ants, probably due to constraints on the production of rewards. This study reports for the first time the anatomical and histological limitations constraining the production of extrafloral nectar in young plants, and the implications that the absence of protective ants imposes for plants early during their ontogeny are discussed.

Methods

Juvenile, pre-reproductive and reproductive plants of Turnera velutina were selected in a natural population and their extrafloral nectaries (EFNs) per leaf were quantified. The anatomical and morphological changes in EFNs during plant ontogeny were studied using scanning electron and light microscopy. Extrafloral nectar volume and sugar concentration were determined as well as the number of patrolling ants.

Key Results

Juvenile plants were unable to secrete or contain nectar. Pre-reproductive plants secreted and contained nectar drops, but the highest production was achieved at the reproductive stage when the gland is fully cup-shaped and the secretory epidermis duplicates. No ants were observed in juvenile plants, and reproductive individuals received greater ant patrolling than pre-reproductive individuals. The issue of the mechanism of extrafloral nectar release in T. velutina was solved given that we found an anatomical, transcuticular pore that forms a channel-like structure and allows nectar to flow outward from the gland.

Conclusions

Juvenile stages had no ant protection against herbivores probably due to resource limitation but also due to anatomical constraints. The results are consistent with the growth-differentiation balance hypothesis. As plants age, they increase in size and have larger nutrient-acquiring, photosynthetic and storage capacity, so they are able to invest in defence via specialized organs, such as EFNs. Hence, the more vulnerable juvenile stage should rely on other defensive strategies to reduce the negative impacts of herbivory.     

Seasonal changes in populations of the orchid Goodyera repens Br. and in its mycorrhizal development

Summary

Population dynamics of Goodyera repens Br. were investigated on permanent quadrats over a 12 month period in conjuction with a study of mycorrhizal infection. The production and death of individuals were recorded at monthly intervals. At all sites production of new individuals was greatest during summer and lowest in winter; deaths were not so markedly seasonal. Recruitment was greater than mortality and the population size increased at all sites. The turnover time of the populations was related to their size and was greater in large populations. The level of mycorrhizal infection in the roots remained constant throughout the year but in the main rhizomes infection was greater in winter when their rate of extension was least. The pattern of infection suggests that internal mycelial spread takes place throughout the year together with some re-infection from the soil.     

Interspecific competition in Australian honeyeaters—depletion of common resources

Many species of honeyeaters and other nectar-feeding birds occur in most habitats in South Australia. They frequently feed on nectar of the same species of plants. A succession of species of plants provide nectar for birds throughout the year. Nectar is most abundant in winter and early spring and least abundant in summer and autumn. There is more nectar per flower and more flowers in winter and spring. Nectar is often depleted by honeyeaters, and sometimes other visitors (silvereyes, lorikeets and insects) between December and May. It is at times reduced to a level at which it is uneconomical for some species to exploit. There are seasonal movements of honeyeaters into areas of abundant nectar and out of these areas when nectar becomes scarce. Breeding coincides with peak abundance of nectar. Diversity of honeyeaters is probably maintained by an interaction of two types of competition, exploitation and interference. The larger species use the richest sources of nectar and aggressively exclude the smaller species (interference) whereas the smaller species can use poorer sources of nectar because their energy requirements are less (exploitation).     

Staging site fidelity of Greenland White-fronted Geese Anser albifrons flavirostris in Iceland

Capsule Based upon resighting histories of marked individuals, a high level of site loyalty was found for Greenland White-fronted Geese staging in Icelandic stopover areas in spring and autumn.

Aims To determine levels of within- and between-season staging site fidelity, to assess whether offspring adopt the staging areas of their parents and to determine relationships between Icelandic staging areas and winter provenance of individuals.

Methods Sequential resighting histories and recoveries (2658 observations) of 415 different individually marked geese were analysed from the period 1986–99.

Results In spring, > 90% of goslings associated with parents and siblings and all goslings were subsequently seen <4 km from where they were first sighted with parents in spring. Ninety-six percent of all multiple within-spring resightings of 192 marked individuals were within 4 km of each other; three geese moved 88 km from the southern to the western staging areas. Four percent of the 45 marked geese seen in two consecutive springs and none of the 27 birds seen in consecutive autumns moved more than 4 km between years. By contrast, significantly more (12%) moved greater than 4 km in subsequent seasons between spring/autumn (n = 56) and autumn/spring (n = 49). All these individuals shifted to Hvanneyri Agricultural College in autumn, the only declared hunting-free area for Greenland White-fronted Geese. Based upon resighting histories and recoveries of shot birds, Scottish wintering birds were more likely to use southern staging areas, and Wexford (Ireland) wintering birds were generally more likely to be seen staging in the western lowlands in Iceland.

Conclusions Given the apparent cultural reinforcement of patterns of use of staging areas in Iceland, the high levels of site loyalty and the relatively limited exchange between southern and western staging areas, we argue for strategic refuge designation throughout both staging areas to protect the population.     

Leaving on migration: estimating departure dates of Barn Swallows Hirundo rustica from summer roosts using a capture–mark–recapture approach

Capsule Capture–mark–recapture data can be used to predict departure dates of Barn Swallows Hirundo rustica from summer roosts.

Aims To investigate how long Barn Swallows remain at their breeding grounds before migration by estimating departure dates.

Methods A capture–mark–recapture approach was applied to an extensive data set (65?303 ringed and 710 recaptured birds) from two summer roosts. Multiple-day constancy models were used to estimate apparent survival, which was subsequently translated to residence time.

Results The longest intervals between ringing and recapturing were between 66 and 67 days; estimated mean minimum durations were between 16.3 and 18.5 days. Apparent survival was high over most of the summer, indicating that there is little emigration during this period and was followed by a sharp departure-related decline in late August and September. Expected residence time, derived from apparent survival estimates, declined linearly from about 80 days in early July to less than 10 days in September. Estimated departure dates were highly consistent between years and occurred in late September.

Conclusions Barn Swallows stay much longer at post-breeding roost sites than is necessary to build up their fat reserves for migration. We suggest that the birds are likely to derive a number of benefits from such a prolonged stay that are not directly related to preparation for migration; for example, minimizing predation risk by foraging in familiar areas, and gathering information on the quality of future breeding sites.     

Growth of opossums (Trichosurus vulpecula) in the Orongorongo Valley,Wellington, New Zealand, 1953–61

The growth of pouch young and juvenile Trichosurus vulpecula to maturity is described, based on animals gin‐trapped in 800 ha of indigenous forest in the Orongorongo Valley, near Wellington. Commencing in March 1953 opossums were trapped continuously for 1 year, and then intermittently until 1961. Four ageing criteria were considered: ossification of limb epiphyses and development of cranial ridges were unreliable; tooth wear and closure of the spheno‐occipital skull sutures were more satisfactory, and were adopted. For the first 180 days the mean growth followed a rectilinear regression when size, expressed as cube root of weight, was plotted against age. Thereafter growth accelerated greatly, but steadied towards the end of the first year; its rate increased after several months, and ceased at 2 to 21/2 years. Though adult males (2.65 kg) and females (2.41 kg) differed significantly in weight, there was no detectable difference during the growth phase. Births occurred throughout the year, but were markedly seasonal, 86% occurring between mid March and the end of May. A secondary birth peak in spring, recorded in other areas, was barely apparent. Most young consequently grew fastest in their first spring and summer. The growth pattern appeared to be mainly dependent on age rather than season_^ since all young reared in captivity conformed, irrespective of the season of birth.     

Commonness of not-so-common birds: the need for baseline knowledge of actual population size for the validation of population size predictions

Capsule The hypothesized regional population size of a common species in Spain was found to be unreliable when compared with a complete and simultaneous single-species direct census.

Aims To provide a regional census of Eurasian Jackdaws Corvus monedula as an example to highlight the crucial importance of baseline knowledge of actual population size of common species for validation and calibration of population size predictions derived from extrapolation.

Methods Population size was measured by means of simultaneous counts of winter communal roosts after determining the best census date and other relevant information on flock routines, foraging areas and potential sources of count variability.

Results A large discrepancy between hypothesized (～330?000 individuals) and directly censused population size (～15?000 individuals) was recorded.

Conclusion Programmes aimed at establishing population size of wildlife by statistical inference should attempt to explicitly test their predictions by comparison with directly censused population sizes of particular species in control areas.     

Decline of Corn Buntings Emberiza calandra on east Scottish study areas in 1989–2007

Capsule Adult numbers on many study areas fluctuated from year to year, but overall showed a large decline, down to extinction on most areas.

Aims To measure changes in summer numbers of adult Corn Buntings in a large sample of study areas holding discrete localized populations.

Methods Singing cocks and hens paired with them were counted in early summer at 30 study areas on farmland from south Angus to central Aberdeenshire. Sixteen populations occurring throughout 1989–95 were called ‘groups’. Counts also included 16 cases where a new ‘offshoot’ appeared in late May or the start of June, not having been seen earlier in that spring or in the previous winter or summer.

Results Following relative stability in 1989–95, large declines occurred in 1995–96, 1998–99 and 2003–04, and decreases far outweighed occasional increases between consecutive summers. The numbers of established groups, new offshoots, and older offshoots all declined with the year. Although containing one to nine founding pairs, new offshoots became extinct later, in six cases after one summer. No new offshoot was seen after 1995.

Conclusions Although 22 study areas held birds in 1989 and 25 in 1990, this fell to 10 in 1999, seven in 2005, and four in 2007 (the only areas that held birds in all years). On all areas combined, cock numbers fell by 83% between 1989 and 2007. Targeted implementation of appropriate agri‐environment measures is urgently needed to halt and reverse such declines, a challenge made all the greater within the last year by rising grain prices, delays to the introduction of new measures, and abolition of EU ‘set‐aside’ as a means for providing food and nesting habitat.     

Effects of the doubly labelled water procedure on Great Tits Parus major feeding young

Capsule Female feeding rate behaviour was highly variable between individuals but no effect of the doubly labelled water (DLW) procedure on female visit rate was detected, whereas visit rates by males, which were neither trapped or manipulated, increased following trapping and manipulation of their partners.

Aims To test the assumption that the subject's behaviour is normal during the measurement period when using DLW to measure energy expenditure.

Methods Visits to the nestbox by parents feeding young were counted separately for females and males on the day before and the day after the female only was trapped to measure her energy expenditure using DLW. Visit rates were also counted for control pairs.

Results Female visit rates did not differ before and after manipulation, or between experimental and control pairs, but bird behaviour was highly variable between individuals. In contrast, the visit rates of both experimental and control males, which were not trapped, increased on the second day.

Conclusion The results for female behaviour supported the assumption of normality, but a small subset of particular individuals may be prone to adverse reactions. The response of the males may have been a reaction to disturbance at the nest.     

CHAFFINCHES FRINGILLA COELEBS DO NOT LEARN SONG DURING AUTUMN AND EARLY WINTER

ABSTRACT

According to the literature, young chaffinches learn conspecific song during the first ten months of their lives. We have shown here that under natural light conditions captive birds do not learn song in October and November and that only one out of ten males was able to learn in December/January. This gap in the ability to learn from first summer to the beginning of the second calendar year is not age-dependent but seems to be hormonally controlled.     

Differences in the diurnal and nocturnal use of intertidal feeding grounds by Redshank Tringa totanus

Capsule Redshank used more sites and had larger ranges at night than during the day.

Aims To determine whether there were differences in how wintering Redshank used intertidal feeding grounds during the day and night.

Methods The movements of 38 Redshank caught and radiotagged at two neighbouring sites on the Severn Estuary were monitored during four different study periods between January 1997 and October 1999.

Results Individuals used a greater number of sites at night than in the day (on average, two as opposed to one). Kernel home range analyses also indicated that individuals used larger core areas and home ranges at night. In addition, there was a significant difference between the sizes of ranges of birds caught at two neighbouring sites. One foraging site was almost entirely avoided during the day, probably due to disturbance from an adjacent heliport, but was used by the majority of individuals at night when the heliport was unused. This site was rich in invertebrates as a result of the high organic and nutrient input from a sewage outfall pipe. Redshank also used riverine mudflats less during the night, preferring more open mudflats – perhaps to avoid nocturnal predators.

Conclusions Comparison with previous studies suggests that the importance of sites predominantly used at night and the total extent of the areas used by waders may be underestimated by studies that rely on daytime surveys alone. It is important, therefore, that information on nocturnal distributions should be available to inform decisions on site management and protection.     

A nocturnal Provespa wasp species as the probable pollinator of epiphytic orchid Coelogyne fimbriata

Many vespid wasps visit flowers to forage nectar. These hymenopterans sometimes contribute to flower pollination. However, none of the nocturnal wasp species is a known pollinator. We collected individuals of light‐attracted Provespa nocturna workers in a montane rainforest on Peninsular Malaysia: some wasps collected bore orchid pollinia on their thoraxes. Among 114 trapped individuals, four bore pollinaria and nine bore only viscidia, suggesting that pollinia had been successfully transported. Molecular barcoding of the pollinia (based on their ITS sequences) assigned the orchid to a species in Coelogyne fimbriata complex. These findings and our other analyses suggest that this nocturnal wasp contributes to pollination of an epiphytic nectarless orchid that probably releases olfactory attractants. This discovery sheds light on the importance of mutualistic relationships between the nocturnal social wasps and epiphytic orchids in Southeast Asian tropical rainforest canopies.