Jerzy Bańbura

The design of artificial nestboxes for the study of secondary hole-nesting birds: a review of methodological inconsistencies and potential biases

Abstract. The widespread use of artificial nestboxes has led to significant advances in our knowledge of the ecology, behaviour and physiology of cavity nesting birds, especially small passerines. Nestboxes have made it easier to perform routine monitoring and experimental manipulation of eggs or nestlings, and also repeatedly to capture, identify and manipulate the parents. However, when comparing results across study sites the use of nestboxes may also introduce a potentially significant confounding variable in the form of differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained. However, the use of nestboxes may also introduce an unconsidered and potentially significant confounding variable due to differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained. Here we review to what extent the characteristics of artificial nestboxes (e.g. size, shape, construction material, colour) are documented in the ‘methods’ sections of publications involving hole-nesting passerine birds using natural or excavated cavities or artificial nestboxes for reproduction and roosting. Despite explicit previous recommendations that authors describe in detail the characteristics of the nestboxes used, we found that the description of nestbox characteristics in most recent publications remains poor and insufficient. We therefore list the types of descriptive data that should be included in the methods sections of relevant manuscripts and justify this by discussing how variation in nestbox characteristics can affect or confound conclusions from nestbox studies. We also propose several recommendations to improve the reliability and usefulness of research based on long-term studies of any secondary hole-nesting species using artificial nestboxes for breeding or roosting.

Breeding Ecology of Whiskered Terns in Algeria, North Africa

Abstract The distribution of the Whiskered Tern (Chlidonias hybridus) is scattered, numbers fluctuate and they are threatened in many regions. Its breeding ecology has only occasionally been studied so far. It is relatively common in some North African wetlands. This study was carried out on Lake Tonga, northern Algeria, south of El-Kala (3651’N; 0820’E) in 1996 and 1997, with 169 and 215 initiated clutches studied, respectively. Basic characteristics of the Whiskered Tern breeding ecology studied were: laying date, clutch size, hatchling number, nest size and shape and egg size. Hatching success differed significantly between 1996 and 1997, probably due to weather. Laying date did not influence breeding parameters. Clutch size and hatching success were correlated with size and shape of nests. Hatchability was also correlated with egg length (negatively) and mass (positively). Relationships between breeding characteristic in relation to weather are discussed.

Nestling diet variation in an insular Mediterranean population of blue tits Parus caeruleus: effects of years, territories and individuals

Mediterranean evergreen forests of Corsica are characterized by relatively high species diversity of arthropods with low population densities. Food is never superabundant for Corsican blue tits Parus caeruleus. This study focused on the composition of the food of blue tit nestlings and especially on two main components, caterpillars and spiders. The nestling diet was studied for two years using 8-mm cameras that automatically took photographs of adult birds with food. The diet was composed of c. 50% caterpillars and c. 30% spiders. There were between-year and between-individual differences in these proportions. In both years of the study the proportion of caterpillars declined during the course of the breeding season. Individual and time effects on prey sizes were also observed. Pairs and individuals were fairly constant in the proportions of prey over the feeding period. Different food items were not brought in runs. These findings suggest that strong food limitation exists on Corsica, which can considerably influence life-history traits of the blue tit.

Food handling time of Blue Tit chicks : constraints and adaptation to different prey types

Extensive literature shows that lepidopteran larvae constitute the most important component of the diet of nestling tits (Parus spp.). In Blue Tits Parus caeruleus, breeding is usually timed to match the nestling stage to the period when caterpillars are most abundant. This is true even in places where caterpillars are not very numerous and many alternative prey types have to be used. in a study of a Corsican Blue Tit P. c. ogliastrae population, characterised by the extensive use of non-caterpillar prey, we compared some aspects of the behaviour of nestlings when fed caterpillars, grasshoppers and spiders. The expectation deduced from ecological and behavioural literature that nestlings should be best able to swallow caterpillars was confirmed. Chick prey handling time could be ranked from caterpillars (the shortest time), through spiders to grasshoppers (the longest time). Handling time increased exponentially with prey size within each prey category and was to some extent subject to variation between broods. Consequently, the behaviour of nestlings provides new support for the idea that Blue Tits are best adapted to eating caterpillars and that mechanical constraints prevent them from using very big prey items, especially non-caterpillar prey, and that this is likely to affect their choice of prey. Such constraints may be less strict in Great Tits Parus major because of their larger body size.

Effects of nest characteristics on breeding success of Great Tits Parus major

Abstract. In this study, nest characteristics (size and proportions of basic components) were not correlated with the timing of breeding. Clutch size was negatively correlated with total nest mass but positively correlated with the proportion of the mass of the lining in the total nest mass. Analyses of hatching and fledging success showed that the quantity and proportion of moss in the nest structure as well as the nest size influenced the performance of eggs and nestlings at the nest. We suggest that variation in nest size and composition may be due to several contradictory pressures associated with the need to keep the moisture and temperature in the nest relatively constant, to protect the brood from predation, and to control sanitary standards.

Effects of Protocalliphora Parasites on Nestling Food Composition in Corsican Blue Tits Parus caeruleus: Consequences for Nestling Performance

Abstract. The influence of a parasite (larvae of Protocalliphora, Diptera: Calliphoridae) on an avian host (Blue Tit) was studied in 1994–1997 as part of a long-term research project on a population of Blue Tits inhabiting nest boxes on the island of Corsica. The Blue Tit broods were heavily infested with Protocalliphora larvae. The abundance of caterpillars as a key food type for the tits was monitored. A random sample of 16 nests was experimentally subjected to an anti-parasite heat treatment, which resulted in a marked decline in the numbers of Protocalliphora larvae. Untreated nests, with high numbers of parasites, were regarded as control nests. Under the anti-parasite treatment, Blue Tit nestlings were fed less frequently than the control nestlings (8 v. 11 food items per hour per nestling). Significant changes in the diet composition occurred, with parasite-free nestlings being consistently fed with fewer caterpillars. An average parasitised nestling was supplied by its parents with 2.6 caterpillars more than an average parasite-free chick. This suggests that in the highly parasitised control nests, the parent tits made an effort to compensate for the detrimental effects caused by Protocalliphora larvae. Feeding rate and food composition were shown to influence chick condition and survival in the nest. In spite of these facts, the nestlings in parasitised nests developed less rapidly and had lower survival rates than in the anti-parasitically heat-treated nests. The parasitic Protocalliphora larvae have a double effect on their avian host: they adversely affect nestling performance, and they compel adult tits to work harder in order to at least partially compensate for that influence.

Avian Feathers as Bioindicators of the Exposure to Heavy Metal Contamination of Food

The aim of this study was to determine the possibility of using feathers of blue tit nestlings to assess the level of endogenous accumulation of lead. For this purpose we conducted an experiment with lead application to randomly chosen nestlings from eight randomly drawn broods. Five days after the exposure, feathers of lead-treated nestlings had significantly higher lead concentrations than control nestlings. This result suggests that feathers can be used as reliable non-destructive bioindicators to assess the level of heavy metals originating from contaminated food, which is of great significance for comparative studies on ecological consequences of pollution.

Variation in clutch size in relation to nest size in birds

Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nests of 21 species of hole and non-hole-nesting birds. There was a significant, positive relationship between clutch size and the base area of the nest box or the nest, and this relationship did not differ significantly between open nesting and hole-nesting species. The slope of the relationship showed significant intraspecific and interspecific heterogeneity among four species of secondary hole-nesting species, but also among all 116 slope estimates. The estimated relationship between clutch size and nest box base area in study sites with more than a single size of nest box was not significantly different from the relationship using studies with only a single size of nest box. The slope of the relationship between clutch size and nest base area in different species of birds was significantly negatively related to minimum base area, and less so to maximum base area in a given study. These findings are consistent with the hypothesis that bird species have a general reaction norm reflecting the relationship between nest size and clutch size. Further, they suggest that scientists may influence the clutch size decisions of hole-nesting birds through the provisioning of nest boxes of varying sizes.

Within-clutch repeatability of egg dimensions in the Black-headed GullLarus ridibundus

Within-clutch repeatability of length, breadth and volume of eggs of the Black-headed GullLarus ridibundus was studied in Central Poland (1981–1983). Significant repeatabilities of all traits were recorded and ranged from 0.510 to 0.607 for all clutch size categories pooled. The results suggest that in the studied population one should expect relatively low or intermediate heritability of egg dimensions. Zwischen 1981 und 1983 wurden in Polen die Wiederholbarkeit von Eilänge, -breite und-volumen innerhalb eines Geleges am Beispiel der Lachmöwe untersucht. Über alle Gelegegrößen hinweg ergeben sich signifikante Werte dieser Wiederholbarkeit zwischen 0.510 und 0.607, die aber unter den verfügbaren Vergleichsdaten für andere Vogelarten liegen. Da die Wiederholbarkeit eine Schätzung der Obergrenze der eigentlichen (unbekannten) Erblichkeit eines Merkmals darstellt, muß man davon ausgehen, daß in der untersuchten Lachmöwenpopulation die Erblichkeit von Eimaßen relativ gering ist.

Clutch-size variation in Western Palaearctic secondary hole-nesting passerine birds in relation to nest box design

Secondary hole-nesting birds that do not construct nest holes themselves and hence regularly breed in nest boxes constitute important model systems for field studies in many biological disciplines with hundreds of scientists and amateurs involved. Those research groups are spread over wide geographic areas that experience considerable variation in environmental conditions, and researchers provide nest boxes of varying designs that may inadvertently introduce spatial and temporal variation in reproductive parameters. We quantified the relationship between mean clutch size and nest box size and material after controlling for a range of environmental variables in four of the most widely used model species in the Western Palaearctic: great tit Parus major, blue tit Cyanistes caeruleus, pied flycatcher Ficedula hypoleuca and collared flycatcher F.albicollis from 365 populations and 79610 clutches. Nest floor area and nest box material varied non-randomly across latitudes and longitudes, showing that scientists did not adopt a random box design. Clutch size increased with nest floor area in great tits, but not in blue tits and flycatchers. Clutch size of blue tits was larger in wooden than in concrete nest boxes. These findings demonstrate that the size of nest boxes and material used to construct nest boxes can differentially affect clutch size in different species. The findings also suggest that the nest box design may affect not only focal species, but also indirectly other species through the effects of nest box design on productivity and therefore potentially population density and hence interspecific competition.