Long-term consequences of early ontogeny in free-living Great Tits Parus major

Environmental factors during early development may have profound effects on subsequent life-history traits in many bird species. In wild birds, sex-specific effects of early ontogeny on natal dispersal and future reproduction are not well understood. The objective of this work was to determine whether hatching date and pre-fledging mass and condition of free-living Great Tits Parus major have any subsequent effect on individuals’ natal dispersal and reproductive performance at first breeding. Both males and females dispersed longer distances in coniferous than in deciduous forests, while dispersal was condition-dependent only in males (heavier as nestlings dispersed farther). In females, mass and condition at pre-fledging stage correlated significantly with clutch size, but not with subsequent reproductive performance as measured by fledging success or offspring quality. In contrast, heavier males as nestlings had higher future fledging success and heavier offspring in their broods compared with those in worse condition as nestlings. The hatching date of female as well as male parents was the only parental parameter related to the number of eggs hatched at first breeding. These results indicate that pre-fledging mass and condition predict subsequent fitness components in this bird species. We suggest that sex-specific relationships between a disperser’s condition and its selectivity with respect to breeding habitat and subsequent performance need to be considered in future models of life-history evolution.     

Variation of adult Great Tit Parus major body condition and blood parameters in relation to sex, age, year and season

In recent years, an increasing number of studies have focused on the ranges of variation of health related biochemical and haematological parameters in wildlife, but information is still scarce for enzymatic activities which can be extremely important in detecting potential responses to environmental change. In a Great Tit (Parus major) population, we describe the variation in relation to age, sex, season and year of: (1) morphological: body condition index, fat and muscle, (2) haematological: hematocrit, haemoglobin, white blood cell count and heterophil/lymphocyte ratio, and (3) biochemical parameters: plasma protein and activities of plasma cholinesterases (acetylcholinesterase and butyrylcholinesterase) activity and red blood cell glutathione peroxidase. Sex had significant effects on all morphological parameters except fat. Age significantly affected cholinesterase activities, H/L ratio and haemoglobin, and there was a significant interaction between sex and age affecting hematocrit. There were significant interactions of year and season affecting almost all parameters studied—body condition index, fat, protein, acetyl and butyrylcholinesterase activities, glutathione peroxidase activity and haemoglobin. This study indicates that these parameters are largely influenced by year and seasonal effects, besides the individual’s intrinsic variation. Therefore, when evaluating experimental or environmental change effects, appropriate controls should be used.     

Selection for fast and slow exploration affects baseline and stress-induced corticosterone excretion in Great tit nestlings, Parus major

In nestlings, glucocorticoid (GC) secretion has short-term and long-term f itness consequences. For example, short-time elevations trigger begging activity, whereas chronically elevated GC levels impair body condition, growth and cognitive abilities. Despite a growing body of literature on personality traits, the effects of selection for fast and slow exploration on GC secretion have received little attention. We compared baseline and stress-induced hypothalamic–pituitary–adrenal (HPA) axis activity of hand-reared great tit nestlings of lines selected for fast and slow exploration. Nestling droppings were collected under three conditions: control, test (following handling stress, day 14 after hatching) and the following day. The concentrations of excreted immunoreactive corticosterone metabolites (CM) were determined via an enzyme immunoassay. We also observed nestlings' begging behaviour. CM differed significantly between the lines. Nestlings of the fast line excreted lower CM than slow-line birds. In response to handling stress, nestlings excreted significantly higher concentrations of CM than during the control and on the day after handling. Sex and begging activity were not related to CM levels. Under the control condition, but not after handling, males begged significantly more often than females. In both lines, adults excreted significantly less CM compared to nestlings. Both nestlings and adults of the slow line produced higher baseline CM values than fast-line birds. Fast-line nestlings excreted lower baseline CM than nestlings of a wild population not selected for fast or slow exploration. Slow-line nestlings did not. Our results show that selection on the basis of exploratory behaviour affected HPA axis reactivity.     

Manipulation of laying effort reveals habitat-specific variation in egg production constraints in Great Tits (Parus major)

It has been suggested that a bird's clutch size is not limited by the amount of resources available at the time of laying but that differences in the availability of food for nestlings is the ultimate underlying factor determining spatio-temporal variations in clutch size. However, habitat-related variations in egg production ability has yet to be investigated explicitly. We studied the breeding of Great Tits Parus major in deciduous and coniferous forests in the same area. The sizes of both the clutches and the eggs were, on average, larger in the former habitat than in the latter. A number of females were induced to lay more eggs than usual by removing four eggs from designated experimental clutches early in the laying period. These manipulated females laid approximately one egg more than control females, with the number of additional eggs laid not differing between the habitats. However, in both study years the relative size of the extra eggs – relative to the mean size of earlier laid eggs of the same clutch – was smaller in the coniferous habitat than in the deciduous habitat, while there was no habitat-related difference in the relative size of the last-laid eggs of control clutches. This result indicates that some form of proximate limitation during egg-laying period can contribute to the relatively small clutches and eggs in the coniferous habitat. Our results emphasize the need to take egg production costs into account when attempting to account for spatial variation in the reproductive behaviour of birds.     

Breeding success and lutein availability in great tit (Parus major)

The relationship among temporal variation in the availability of carotenoid-rich food, tissue carotenoid levels and breeding success are poorly known. We studied how diet quality and quantity affect the carotenoid profile and fledging success of great tit (Parus major) nestlings along a pollution gradient. We found declining seasonal trend in lutein concentration of caterpillars, which may be the explanation for the declining trend in nestlings' lutein concentration of plasma with season, despite the increase in caterpillar biomass. This may be because the biomass of most lutein-rich caterpillars (autumnal moths) decreased and less lutein-rich caterpillars (sawflies) increased during the breeding season. The temporal difference in occurrence of different caterpillar species means that peak lutein availability does not coincide with peak caterpillar abundance. However the positive association between total larval biomass and the number of great tit fledglings may suggest that fledging success depends more on total caterpillar availability than on lutein concentration of caterpillars.     

Experimente zur Bruth?hlenwahl der Kohlmeise (Parus major)

Zusammenfassung Obwohl die Kohlmeise in sehr verschiedenen Höhlen brütet, zeigt die Art eine signifikante Bevorzugung, wenn sie die Möglichkeit zur Auswahl hat. Versuche mit Holzbetonnisthöhlen ergaben eine eindeutige Präferenz tiefer Höhlen von 19 cm Tiefe (vom Flugloch ab) gegenüber Höhlen von 14 oder 9 cm Tiefe. Noch tiefere Höhlen wurden abgelehnt, ebenso horizontal verlaufende. Bruthöhlen mit großem Innenraum von 20 cm Durchmesser wurden gegenüber Modellen von 14 oder 11,5 cm bevorzugt. Der große Brutraum wurde gegenüber tieferen, aber engeren Höhlen bevorzugt; eine solche Höhle sollte 14 cm tief und nicht 19 cm tief sein. In der Diskussion wird ein möglicher Selektionsvorteil in der Sicherheit vor Nestfeinden sowie der besseren Isolation des Nistmaterials gegenüber engeren Höhlen vermutet. Der Bruterfolg ist in großen Höhlen infolge größerer Gelege am größten.

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Experiments on nest-site selection in Great Tit,Parus major

Summary Although the Great Tit nests in a wide variety of holes, it shows a significant preference when a choice is available. Experiments with cement-sawdust nest-boxes indicated a clear preference for deep boxes of 19-cm depth (measured from entrance hole) over boxes 14 or 9 cm deep. Still deeper boxes were rejected as were those horizontally mounted. Nest-boxes with large internal space of 20-cm diameter were preferred to models of diameter 14 or 11.5 cm. The large box was preferred to deeper boxes with smaller internal diameter; such a box should be 14 and not 19 cm deep. It is suggested in the discussion that the larger-diameter box offers a possible selective advantage over smaller models in security against nest-predators as well as better insulation in the form of more extensive nest material. Breeding success is highest in large-diameter boxes due to larger clutches.

     

Experimentelle Untersuchungen zur Brutbiologie von Kohl- und Blaumeise (Parus major undP. caeruleus)

Zusammenfassung 1. Für die vorliegende Arbeit wurden Untersuchungsbefunde aus dem Jahr 1969 an 53 Kohlmeisen- und 39 Blaumeisen-Erstbruten eines Laubwaldgebietes bei Braunschweig ausgewertet.2. Blaumeisen begannen gesichert um 2 1/2 Tage früher mit der Eiablage als Kohlmeisen. Zwischen den Altersstufen einer Art konnten dagegen keine Unterschiede festgestellt werden.3. Unterbrechungen in der Eifolge bei Kohl- und Blaumeise wurden möglicherweise durch Temperaturstürze hervorgerufen.4. Die intraindividuelle Variabilität der Eidimensionen (Eilänge, Eibreite und kalkuliertes Eivolumen) war stets signifikant geringer als die interindividuelle Variabilität. Für Eibreite und Eilänge ergab sich bei beiden Arten eine positive Korrelation.5. Einjährige Kohlmeisen legten gesichert längere und breitere Eier als mehrjährige Tiere; bei der Blaumeise konnten in der Eigröße keine diesbezüglichen Unterschiede festgestellt werden.6. Bruten mit mittelgroßer Eizahl wiesen bei beiden Arten im Durchschnitt die größten Eier auf. Innerhalb eines Geleges waren in der Regel die zuletzt gelegten Eier größer als die zuerst gelegten.7. Fortnahme bzw. Hinzulegen von Eiern während der individuellen Legeperiode hatte bei den Weibchen eine gesichert höhere bzw. niedrigere Eiproduktion im Vergleich zu einer Kontrollgruppe zur Folge. Kohl- und Blaumeisen sind somit als indeterminierte Leger zu bezeichnen.8. Die durchschnittliche Brutdauer betrug bei der Kohlmeise 13,9 und bei der Blaumeise 14,6 Tage.9. Die Reihenfolge des Schlüpfens war bei den zuerst gelegten Eiern häufiger unregelmäßig.10. Nestlinge großer Bruten waren bei beiden Arten leichter als gleichalte Junge kleiner Bruten.11. Die Nestlingsdauer betrug im Durchschnitt bei der Kohlmeise 18,8 und bei der Blaumeise 19,9 Tage. Zwischen verschieden großen Bruten konnte kein Unterschied in der Nestlingsdauer festgestellt werden.

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Summary 1. In 1969, 53 first broods of Great Tits and 39 first broods of Blue Tits were studied in mixed deciduous woodland near Brunswick.2. On the avarage Blue Tits laid significantly (2 1/2 days) earlier than Great Tits. No differences could be found in the date of laying between different age groups within a species.3. In both species, a drop in temperature may possible cause a 1–2 days' interruption in laying.4. There was significantly less variation among different eggs (length, breadth, and calculated volume) laid by the same bird than among the average egg characteristics of different birds. In both species, there was a positive correlation between length and breadth of the egg.5. Avarage breadth and length of eggs were significantly bigger in one-year old Great Tits than in older birds. Such differences did not exsist in Blue Tits.6. Eggs from avarage-sized clutches were bigger than those from very small or very large clutches. As a rule, the last egg of a clutch were bigger than the first ones.7. Compared with the clutch size of a controll group, daily removal of eggs or addition of eggs. — soon after the onset laying — resulted in an increase or in a reduction of the clutch size, respectively. Consequently, Great and Blue Tit may be considered as indeterminate layers.8. The mean incubation period of the Great Tit was found to be 13,9 days, that of the Blue Tit 14,6 days.9. The first eggs of a clutch frequently did not hatch in the order they were laid.10. In both species, nestlings of large-sized broods avaraged lighter than nestlings of smaller-sized broods.11. The mean nestling period of the Great Tit was found to be 18,8 days, that of the Blue Tit 19,9 days. There was no difference between the nestling period in large and small broods.

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Herrn Dr. Rudolf Berndt zum 60. Geburtstag in Dankbarkeit gewidmet

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Erweiterte Fassung eines am 10. 10. 1969 auf der 82. Jahresversammlung der Deutschen Ornithologen-Gesellschaft in Münster gehaltenen Vortrages. Materialsammlung und -auswertung erfolgten mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Pollination of the Crown ImperialFritillaria imperialis by Great TitsParus major

Visitations of flowers of the Crown Imperial by Great Tits at two different locations in Hessen, Germany, in 1990 and 1993 are described. The observations prove that flowers were visited because of the nectar; most likely pollination occurs during this visits. Similar reports from Europe are discussed. The significance of specific interactions including ecological generalists such as the Great Tit is considered in the context of the phylogenetic reconstruction of the development of co-adaptive syndroms.

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Zusammenfassung Beobachtungen von Kohlmeisen (Parus major) an Blütenständen der Kaiserkrone (Fritillaria imperialis) in Hessen zeigen, daß der Blütenbesuch des Nektars wegen erfolgte und daß dadurch mit größter Wahrscheinlichkeit eine Bestäubung der Pflanzen erreicht wird. Ähnliche Fälle aus Europa werden diskutiert. Die Bedeutung spezifischer Interaktionen unter Beteiligung ökologischer Generalisten wie der Kohlmeise für die Rekonstruktion der phylogenetischen Entstehung co-adaptiver Syndrome wird erörtert.

     

Body mass of female great tits (Parus major) at egg laying

Based on automated weighing of nest-boxes, we found that female great tits (Parus major) usually maintained their body mass during the egg-laying period. A drop in temperature (3°C or more) during laying was followed by a drop in body mass, and female body mass also depended slightly but significantly on mean temperature on the other days. Day to day change in body mass depended negatively on the actual body mass. Moreover, the repeatability of the morning body mass was high (r _I =0.90, n=24). Thus, female body mass seems to be regulated around a female specific, but temperature-dependent, level during laying. The lack of strong correlation between female average body mass and clutch size makes it improbable that body mass at laying plays a leading, proximate role in the control of clutch-size of great tits.     

Populations?kologische Ergebnisse aus Biomonitoruntersuchungen bei der Kohlmeise (Parus major)

Summary The tail feathers taken from Great Tits sampled in two isolated urban study plots were analysed for their cadmium, lead and zinc content. There were significant differences in heavy metal content between the study plots. These held true both for resident nestlings and immigrants. It was concluded that immigrants had been raised in the immediate vicinity of each study plot. Population exchange between isolated parks and cemeteries on the one hand and between urban habitats and surrounding woods on the other hand is considered to be very low.     

Breeding patterns of great tits ( Parus major ) in pine forests along the Portuguese west coast

The breeding biology of great tits (Parus major) was studied in two forests of maritime pine (Pinus pinaster) on the west coast of Portugal, 200 km apart: Leiria (north) and Aposti?a (south). These two forests are located in a transition zone between Atlantic climate in the north, and Mediterranean climate in the south. Breeding onset was, on average, in the second and third week of March, which are the earliest records of breeding for this species. The southern population started to breed earlier than the northern one and produced a larger first clutch, 8.3 and 7.4 eggs, respectively. Corresponding to larger clutch sizes, we also found a higher first brood fledgling production in Aposti?a compared to Leiria, 6.1 and 5.4 fledglings, respectively. However, the total number of fledglings produced per pair was higher in Leiria (8.3) than in Aposti?a (7.7), due to higher productivity of second clutches (4.7 and 2.7 fledglings, respectively). Accordingly, the allocation of eggs between successive breeding attempts was more equal in Leiria. Results are discussed in accordance to the different climatic patterns in the two areas. It is suggested that the timing of breeding and different allocation of reproductive investment between successive breeding attempts play an important role in optimizing breeding tactics in this facultative multiple-brooded passerine in different climatic areas.     

Relationship between temperature and the timing of breeding of the Blue Tit (Parus caeruleus) in two Mediterranean oakwoods

Summary Correlations between warmth sum and egg laying in tits (Paridae) were often found but do not prove that there is a direct influence of temperature on egg laying date. Such correlations are also open to criticism because they involve a statistical bias (i. e. the selection of variables). Studies of a Blue Tit population in two close but different habitats in Mediterranean France showed that it is better, at least, to consider a time period with a physiological signification (1 January–10 April). We found that the higher the mean temperature in this time period, the earlier the egg laying commenced. Egg laying dates of the Blue Tit in the two habitats are primarily attributed to habitat-related feeding resources.

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Zusammenfassung Die zahlreich publizierten Korrelationen zwischen Wärmesummen und Beginn der jährlichen Legeperiode bei Meisen (Paridae), bilden keinen Beweis für einen direkten Einfluß der Temperatur auf den Legebeginn. Solche Korrelationnen beruhen außerdem auf statistische fraglichen Auswertungen. Untersuchungen an einer Blaumeisenpopulation (Parus caeruleus) in zwei benachbarten, aber verschiedenen Bruthabitaten im mediterranen Südfrankreich zeigten, daß höchstens ein längerer Zeitabschnitt (1. Januar bis 10. April) mit physiologischer Bedeutung in Betracht zu ziehen ist. Je höher die Durchschnittstemperatur in dieser Periode, um so früher der Legebeginn, der jedoch hauptsächlich durch die zeitlich unterschiedlichen Nahrungsangebote in den beiden untersuchten Habitaten erklärt wird.

     

Der Einflu? der H?henlage auf Ei- und Gelegegr??e bei Kohlmeisen (Parus major)

In 7 Untersuchungsgebieten ließ sich ein signifikanter Anstieg im Eivolumen mit zunehmender Höhe nachweisen (Tab. 1). Hingegen wurde die geringste Gelegegröße in einem isolierten Stadtbiotop ermittelt; eine Zu- oder Abnahme der Gelegegröße in Abhängigkeit von der Höhe der Untersuchungsgebiete konnte nicht festgestellt werden (Tab. 2). Der Bruterfolg war im Stadtbiotop (100 m) und im höchstgelegenen Gebiet (875 m) im Vergleich zu Laubund Nadelwäldern in 300 m Höhe sehr niedrig (Tab. 3). Lediglich in der isolierten Stadtpopulation ließ sich eine reduzierte Gelegegröße als Anpassung an die sehr ungünstigen Ernährungsbedingungen erkennen. In der Höhe wird offenbar durch den ständigen Zustrom aus Tallagen eine Anpassung der Gelegegröße an die Höhenbedingungen verhindert. Als Anpassung an die klimatisch schwierigen Bedingungen in größeren Höhen ist die Zunahme der Eigröße mit der Höhe zu werten. Wegen des hohen Genflusses ist diese Anpassung vermutlich nicht genetisch fixiert.Egg size increased significantly from lowland urban habitats (Frankfurt, Hessia, West Germany) to coniferous mountain habitats (Garmisch-Partenkirchen, Bavaria). Clutch size was lowest in urban parks and cemeteries but did not increase or decrease with altitude (Tab. 2). Breeding success was extremely low in urban and mountain habitats compared to deciduous woods in 300 m (Tab. 3). In isolated urban parks a reduction in clutch-size indicates adaptation to poor feeding conditions. The mountain populations are not isolated from lowland ones. Therefore we conclude that perpetual influx of genes from other than mountain populations prevents selection producing a suitable clutch-size. Egg-size on the other hand is well adapted to altitude. Young hatched from large eggs are able to cope better with unfavourable weather conditions regulary met in mountain areas. Because geneflux is high, in mountain populations adaptations in egg-size are unlikely to be fixed genetically.     

Calcium effects on life-history traits in a wild population of the great tit (Parus major): analysis of long-term data at several spatial scales

Calcium is an essential micronutrient for birds during egg formation and for skeletal development in nestlings. Habitat level studies suggest that birds breeding in low-calcium areas may be limited in the size or number of eggs they lay and in the quality of their nestlings. However, as birds forage non-randomly and may travel considerable distances to acquire calcium, describing different breeding environments in terms of their calcium availability is problematic. Here we explore the spatial relationships between 300-fold variation in soil calcium and the life-history traits of ca. 6,000 pairs of great tits breeding in a single continuous woodland over 41 years. Controlling for other habitat differences, we found strong positive associations between soil calcium, clutch size and recruitment at spatial scales of over 300 m from each nestbox, suggesting that females may have been travelling inter-territorially to acquire calcium during egg formation. Soil calcium near each nestbox (mean distance = 58 m) was a strong positive predictor of mean fledgling mass, suggesting that local calcium was more important during nestling stages. We found no effect of soil calcium on lay-date or egg mass. This study is the first to provide evidence that small woodland passerines are limited by calcium availability at several different spatial scales. However, experimental work is necessary to test the causality of these spatial patterns.     

The physiology of hypothermia in the black-capped Chickadee,Parus atricapillus

Summary The shivering, body temperature, and metabolic response to stable and decreasing ambient temperature were measured in winter acclimatized Black-capped Chickadees,Parus atricapillus. Shivering activity, measured by duration and amplitude of bursts, increased curvilinearly from thermoneutral temperatures of 27°C down to 0°C. This parabolic shivering response may be a major component of the curvilinear response of metabolism to decreasing ambient temperature.Birds exposed to 0°C exhibited metabolism 32–45% lower than predicted for a 12-g homeotherm and body temperatures 10°C below the pre-experimental nocturnal body temperature. This hypothermia was not the result of a breakdown in thermoregulation, but was a controlled effort serving to reduce overnight energy expenditure. It is suggested that (1) hypothermia was achieved by decreased shivering by pectoral muscles during exposure to decreasing ambient temperatures, (2) the rate of body temperature decline was moderated by intermittent and reduced bursts during the cooling period, and (3) body temperature was maintained at a particular level during exposure to a stable low ambient temperature by intense bursts lasting one to three minutes.The physiology of hypothermia in chickadees is similar to torpor; however, chickadees did not arouse to a normal diurnal body temperature in the laboratory, and their hypothermia was not induced by inanition or prolonged exposure to cold, as reported for other species capable of torpor.     

Leishmania major: Secreted antigens of Leishmania major promastigotes shift the immune response of the C57BL/6 mice toward Th2 in vitro

BALB/c mice are sensitive to Leishmaniamajor infection, while C57BL/6 mice are resistant and able to mount an effective immune response against the parasite. Since the secreted antigens of L. major suppress the proliferation of BALB/c mice lymphocytes in vitro, we analyzed their effects on the immune system of resistant C57BL/6 mice. Secreted antigens were semi-purified and two fractions with immunosuppressive activity were isolated. 15 μg/ml of fraction could suppress 60% of lymphocyte proliferation and prevent the stimulated lymphocytes entering from G1 phase into the S phase of the cell cycle. These fractions decreased the production of IFN-γ, increased IL-4 level in the lymphocyte culture and down-regulated the nitric oxide production by activated macrophages. These results may suggest that L. major parasite by secreting immunosuppressive factors could down-regulate the immune system of both sensitive and resistant mice for own survival advantage.     

Plasma levels of luteinizing hormone and steroid hormones in free-living winter groups of willow tits (Parus montanus)

Plasma levels of LH, DHT, testosterone, and corticosterone were measured for all members in free-living winter flocks of willow tits, Parus montanus. Hormonal data were related to (1) flock size and (2) age/sex differences. The winter flock defends a large winter territory and shows a well-established social hierarchy in which adults consistently dominate first-year birds. One winter group normally consists of four individuals, two adults and two juveniles. In flocks containing four or five members juvenile willow tits had significantly higher corticosterone values than adults. In small-sized groups, containing three members, all individuals had high plasma levels of corticosterone. No other effects of flock size was found. When data were treated on an age/sex basis, i.e., flock size was not considered, juvenile females were found to have significantly higher plasma levels of testosterone than adult birds, and also significantly higher levels of DHT than juvenile males and adult females. Also, juvenile willow tits had significantly higher plasma levels of corticosterone than adult birds.