Jan Pinowski

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.

Roadkills of vertebrates in Venezuela

Este trabalho apresenta uma analise de vertebrados mortos em estrada em cinco habitats tropicais diferentes na America do Sul. As observacoes dos vertebrados mortos em estrada foram feitas em 1978, a 572 km da rodovia entre Caracas e Mantecal/Apure na Venezuela, durante a estacao das chuvas (junho-outubro). Durante cinco passagens nesta rota, a qual inclui cinco habitats diferentes, foram encontradas 79 carcacas de vertebrados - repteis e mamiferos. Assumindo que as carcacas permanecam por dois dias na estrada, e esperado que veiculos matem 350 crocodilos Caiman crocodilus Linnaeus, 1758 (Alligatoridae), durante a estacao das chuvas. Calculos similares foram feitos para outras 313 especies de cobras e lagartos, 294 gambas Didelphis marsupialis Linnaeus, 1758 (Didelphidae), 220 raposas Cerdocyon thous (Linnaeus, 1776) (Canidae), 129 tamanduas Tamandua tetradactyla (Linnaeus, 1766) (Myrmecophagidae), 55 capivaras Hydrochaerus hydrochaeris (Linnaeus, 1766) (Hydrochaeridae) e 37 lebres Sylvilagus floridanus Allen, 1890 (Leporidae). Numerosos trabalhos tem sido publicados sobre vertebrados mortos por veiculos em estradas da Europa, America do Norte e Australia e varios trabalhos tem sido referencias uteis sobre vertebrados mortos em estradas na Africa e Asia. Da America do Sul existem varios trabalhos com vertebrados, passaros e mamiferos, sendo que da Venezuela existe apenas um que tenha tratado de iguanas (Iguana iguana Linnaeus, 1758, Iguanidae).

The effect of egg size on growth and survival of the tree sparrow Passer montanus nestlings

Abstract. The paper analyses the effect of egg dimensions (volume, breadth, and length) on the growth and development of Tree Sparrow nestlings on successive days of life. Egg size did not influence nestling mortality. It was found that for most days of nestling life, the mean volume and breadth of eggs were positively correlated with the mean mass of nestlings in the nest. Similarly, the deviation of the volume and breadth of a particular egg from the mean egg volume and breadth in the clutch was positively correlated with the deviation of nestling mass from the mean nestling mass in the nest. Nestling growth and development in terms of asymptotic mass (g), maximum growth rate (g/day), tarsus length, and longest remex length were also positively correlated with egg size. The effect of egg size was particularly pronounced in the period of termination of intensive growth rate, development of thermoregulation, and feather development. It is possible that larger eggs contain more microelements, hormones, antioxidants, and vitamins.

Significance of the Breeding Season for Autumnal Nest-Site Selection by Tree Sparrows Passer montanus

Abstract. The Tree Sparrow is one of the species exhibiting classical autumn sexual behaviour. Autumn nest selection by this species was studied in Central Poland, especially with respect to the history of nest-boxes in the previous breeding season. During the autumn display, Tree Sparrows constructed nests significantly more often in boxes that had been occupied in spring by conspecifics, but only rarely in empty boxes, in boxes where House Sparrow Passer domesticus, tits Parus sp., Pied Flycatcher Ficedula hypoleuca, Redstart Phoenicurus phoenicurus had nested, or in boxes used by hymenopterans. During the autumn display, Tree Sparrows showed a preference for boxes where nestlings had hatched. Nests with nestlings in the breeding season are a cue used in selecting nest site in the autumn sexual behaviour.

The Effect of Trends in Ambient Temperature on Egg Volume in the Tree Sparrow Passer montanus

Abstract. The effect of ambient temperature before and during laying on egg volume in birds has been studied by many authors. The objective of this paper is to show that trends in daily temperatures changes can also influence egg volume. The study was carried out near Warsaw, Poland in 1994 and 1995. We ascertained the laying sequence, size and volume of 1070 eggs in 211 clutches of the Tree Sparrow. The effect of the trend in temperature on the mean egg volume in a clutch explained 0.4% of its variation (0.03% to 4.2%, depending on the brood-period), and the effect of actual temperature explained 0.9% (0.5% to 1.6% depending on the brood-period). The joint effect of temperature and its trend explained 3.1% (1.7% to 8.9% depending on the brood-period) of variation in the mean egg volume in a clutch. The authors discuss possible mechanisms of the effect of temperature and temperature trend on egg volume.

Nest Construction During Autumn Display and Winter Roosting in the Tree Sparrows Passer montanus

Abstract. A study of Tree Sparrows was conducted near Warsaw, central Poland. During the breeding season, nest boxes were checked to record the presence of Tree Sparrow nests and broods. Nestlings, juveniles, and adults captured in mist nets were ringed with different combinations of colour rings to identify their age during visual observations in the autumn sexual display period. Before the autumn display, breeding nests were dyed in order to identify nest material added during the autumn display period. In winter, nest boxes were inspected to catch the birds roosting in them at night. The study was conducted in optimal and marginal habitat types. In the optimal habitat during the autumn sexual display, adult birds were much more abundant than in the marginal habitat. During the breeding season, 41% of the nest boxes were occupied in the optimal habitat, compared with 8% in the marginal habitat. The respective figures during the autumn display were 95% and 45%. Autumn nests were built in 83% and 12% of the nest boxes, respectively, and in winter, 35% and 7% of nest boxes, respectively, were used by birds for night-time roosting at night. The autumn display continued from early September to the end of October. For roosting at night in winter (November-March), Tree Sparrows selected nests according to their insulating quality. Most often they roosted in nest boxes containing nests from the breeding season with autumn nests built over them, then, in descending order of frequency, in nest boxes with autumn nests built in empty boxes, in boxes with breeding nests, and in completely empty boxes. Among birds roosting at night and captured on the first survey in winter, 86% were represented by pairs that had built those nests during the autumn display. Young birds that did not build autumn nests typically roosted at night in tree crowns. This implies that the construction of autumn nests is primarily a consequence of the autumn sexual display, and secondarily may be an adaptation for winter survival. The winter survival rate was significantly higher in juvenile Tree Sparrows that were found in nest boxes on winter nights than in those that were not.

Post-breeding courtship: public information about breeding habitat quality?

AbstractAnimals can estimate breeding habitat quality by monitoring social information provided by the behaviours of others. While it is accepted that the value of public information erodes with distance from the source of information, the spatial and temporal ecology of public information acquisition and use is not well understood. Published accounts of the acquisition of public information for breeding habitat selection show a study bias towards the period corresponding to the breeding season. Here, we explored the idea that post-breeding courtship is a reliable source of performance social information about breeding habitat quality that can be used by nest-site prospectors. We revealed that post-breeding courtship can be used as performance social information for breeding habitat selection in a sedentary, cavity-nesting bird species, the Eurasian Tree Sparrow Passer montanus. First, the occurrence of the autumn nest at a nest box was positively associated with the nest box’s breeding performance in both the preceding and subsequent breeding seasons. Second, nest boxes with owners that showed higher post-breeding courtship activities attracted more prospectors. Namely, more prospectors visited nest boxes momentarily occupied by both owners and containing complete autumn nests at the end of autumn compared to nest boxes momentarily occupied by single owners and containing incomplete autumn nests. We suggest that post-breeding courtship represents performance social information about breeding habitat quality that is accessible to more potential observers than performance social information available during the breeding period is. Also, post-breeding courtship can be even more reliable performance social information than that available during the breeding period because it integrates information provided by informed individuals on the nest site’s breeding performance and post-breeding attractiveness (i.e. use).ZusammenfassungBalzen nach der Brut: allgemeine Information über die Qualität des Bruthabitats? Tiere können mit Hilfe sozialer Information, die durch das Verhalten anderer Tiere bereitgestellt wird, die Qualität eines Bruthabitats abschätzen. Während gemeinhin anerkannt ist, dass der Nutzen allgemeiner Information mit der Distanz zur Informationsquelle abnimmt, ist die räumliche und zeitliche Ökologie der Beschaffung und des Nutzens allgemeiner Information nur schlecht verstanden. Viele der publizierten Studien über die Beschaffung allgemeiner Information für die Wahl eines Bruthabitats konzentrieren sich auf die Brutsaison. Hier haben wir die Idee untersucht, dass Balzen nach der Brut eine zuverlässige Quelle sozialer Information über die Qualität des Bruthabitats darstellt und von Tieren, die auf der Suche nach Nistplätzen sind, genutzt werden kann. Wir zeigen, dass Balzen nach der Brut bei einem höhlenbrütenden Standvogel, dem Feldsperling Passer montanus, in der Tat als soziale Information für die Wahl eines Bruthabitats genutzt werden kann. Erstens fanden sich Herbstnester besonders in Nistkästen, wo in sowohl der vorhergehenden als auch der folgenden Brutsaison ein hoher Bruterfolg erzielt wurde. Zweitens zogen Nistkästen, deren Bewohner nach der Brut stärker balzten, mehr nach einem Nistplatz suchende Tiere an. Und zwar besuchten mehr solcher Tiere Nistkästen, die am Ende des Herbstes vorübergehend von beiden Besitzern besetzt waren und vollständige Herbstnester beherbergten, im Vergleich zu Nistkästen, die vorübergehend von nur einem Besitzer besetzt waren und unvollständige Herbstnester beherbergten. Wir stellen die Hypothese auf, dass Balzen nach der Brut soziale Information über die Qualität eines Bruthabitats bereitstellt, die mehr potenziellen Beobachtern zugänglich ist als während der Brutsaison verfügbare soziale Information. Balzen nach der Brut könnte sogar verlässlicher sein als soziale Information zur Brutzeit, weil sie Information über die Brutleistung des Nistplatzes und die Attraktivität nach dem Brüten (d.h. Benutzung) integriert, die von informierten Individuen bereitgestellt wird.

The Effect of Egg Size on Hatching Rate in the Tree Sparrow Passer montanus (Study in Central Poland)

Abstract. The analysis covered 1332 Tree Sparrow eggs, 1053 of them hatched, in 257 clutches of which 114 were fully successful, 119 partially so, and 24 were deserted. The mean egg mass in deserted clutches was lower than in clutches where hatching success was total or partial but not significantly so. The mean hatching success per clutch increased with the mean egg mass. The individual eggs in fully hatched clutches weighed significantly more (2.21 g) than those in partially hatched clutches (2.17 g), and were also heavier than “infertile” eggs (2.14 g). During nest inspections to ascertain the egg laying sequence, the egg mass in 5-egg clutches with full and partial hatching success was found to be higher than in deserted clutches. The eggs in fully hatched clutches were broader than “infertile” eggs.

Laying Interruption in the Tree Sparrow Passer montanus

Abstract. The work was carried out in the villages of the łomianki commune near Warsaw, Poland (52°20′N, 20°50′E) in 1994 and 1995. From among 315 clutches of Tree Sparrows studied, 20 exhibited one-day interruptions in the laying of first and second broods, while 2 were characterised by two-day interruptions. Amongst third broods, there was just a single one-day interruption noted in each year of the study. Interruptions did not occur immediately prior to the laying of the last egg in a clutch. Only in the case of the first brood in 1995 could a period of cold account for interruptions; in the remaining cases, the phenomenon must have been influenced by non-meteorological factors. The Tree Sparrow resembles the House Sparrow Passer domesticus in having far fewer interruptions to laying than other small hole-nesting birds, such as tits Parus spp. This is probably a reflection of the genus Passer having evolved in dry areas, where the accumulation of body reserves in the female prior to laying is an adaptation reducing the length of the breeding period to match the time associated with the rainy season, when food is abundant.

Evaluation of the TOBEC method for calculating fat mass in Tree Sparrows Passer montanus and House Sparrows Passer domesticus

Abstract. Total body electrical conductivity (TOBEC) is the name of a non-invasive method for investigating total body fat (TBF) in vertebrates. The error of measurement depends on body mass (for large animals the relative error is small), body shape and other factors. The ACAN-2 apparatus operating on the basis of the TOBEC method shows integer numbers (readings) correlated with lean body mass (LBM). From the series of these readings (measurements) TOBEC can be calculated in many ways. The error for LBM and TBF measurements in Tree Sparrows (of masses 22.5 ± 1.7 g) and House Sparrows (of masses 29.8 ± 2.0 g) was 1.19 g. This error may be reduced by repeating the TOBEC measurement and calculating the arithmetic mean of readings from the apparatus obtained 1 second after the commencement of measurement. Readings making up a single measurement series showed periodic irregular fluctuations of average amplitude 3 units in the case of Tree Sparrows and 5 units for House Sparrows — corresponding to errors of 0.5 g LBM in both species. Given individuals of both species were characterised by similar differences between the first and second TOBEC measurements. The TOBEC value obtained in a measurement during which a bird defecated in the chamber of the apparatus was significantly higher than that for a bird in a clean chamber. The orientation of the head in the chamber did not influence the repeatability of the TOBEC measurement. In Tree Sparrows, the relationship between TOBEC and LBM differed between those captured and held for one night prior to measurement and those measured for TOBEC immediately after capture.