Tit Species Research Articles

Avoidance of aposematic prey in European tits (Paridae): learned or innate?

Predators may either learn to avoid aposematic prey or may avoid it because of an innate bias. Learned as well as innate avoidance has been observed in birds, but the existing evidence is based on experiments with rather few unrelated model species. We compared the origin of avoidance in European species of tits (Paridae). First, we tested whether wild-caught birds (blue tits, great tits, crested tits, coal tits, willow tits, and marsh tits) avoid aposematic (red and black) adult firebugs Pyrrhocoris apterus (Heteroptera) more than nonaposematic (brown painted) ones. Larger proportion of birds avoided aposematic than brown-painted firebugs in majority of species (except coal tits). Second, we tested whether naive hand-reared birds of 4 species (blue tits, great tits, crested tits, and coal tits) attack or avoid aposematic and nonaposematic firebugs, both novel for them. Behavior of the naive blue tits and coal tits was similar to that of the wild-caught birds; majority of them did not attack the firebugs. Contrastingly, the naive great tits and crested tits behaved differently than the wild-caught conspecific adults; majority of the wild-caught birds avoided the aposematic firebugs, whereas the naive birds usually did not show any initial avoidance and had to learn to avoid the aposematic prey. Our results show that the origin of avoidance may be different even in closely related species. Because blue tits and coal tits avoided not only aposematic firebugs but also their brown-painted form, we interpret their behavior as innate neophobia rather than innate bias against the warning coloration. Copyright 2007.

Leafing phenology and timing of egg laying in great tits Parus major and blue tits P. caeruleus

To evaluate the importance of tree leafing for the start of laying and clutch size of birds, we compared the breeding phenology of great tits Parus major and blue tits P. caeruleus between one coastal and two inland sites in the same geographical region. Because of the cooling influence of the sea, trees at the coastal site were known to initiate budburst about a week later than at the inland sites. During 5 years, breeding by the tits and the leaf phenology of birch Betula pendula, and oak Quercus robur were monitored. The leaf phenology of birch and oak explained a significant part of the between‐year variation in the start of egg laying in blue and great tits, respectively. The tits started laying earlier at the sites with an early budburst, i.e. normally inland. However, leaf phenology was not an absolute cue to the start of laying, since blue tits laid earlier relative to leafing at the inland site than at the coastal site, and both tit species laid eggs earlier relative to leafing during late springs. In neither species was clutch size affected by leafing phenology. However, great tit females at the coastal site consistently produced fewer eggs than did those at the inland site. No such difference was found in the blue tits. Although leafing phenology may predict the start of laying in tits, other factors also influence its timing. These factors might include other cues, or differing life‐history trade‐offs depending on site or general climatic factors during the spring.

Effect of nest box installation density on usage by Tree Sparrow and tit species

Effect of nest box installation density on usage by Tree Sparrow and tit species

Phylogeny of Titmice (Paridae): II. Species Relationships Based on Sequences of the Mitochondrial Cytochrome-B Gene

AbstractWe present a phylogenetic hypothesis for 40 species in the bird family Paridae, based on comparisons of nucleotide sequences of the mitochondrial cytochrome-b gene. Parids, including tits and chickadees, are an older group than their morphological stereotypy suggests. The longest cytochrome-b distances between species reach 12% in uncorrected divergence. With the exception of one thrasher-like terrestrial tit species of the Tibetan plateau (Pseudopodoces humilis), morphological and ecological stasis have prevailed since the initial parid radiation in the Old World during the mid-Tertiary.All trees support monophyly of the family Paridae, which includes Parus (sensu lato) and the monotypic Oriental genera Sylviparus, Melanochlora, and Pseudopodoces. Within the clade of chickadees and gray tits (Parus, subgenus Poecile), three Old World species, Parus lugubris of the eastern Mediterranean and Balkan regions, P. superciliosus of high elevations in the Himalayas of western China, and P. varius of the Orient are sisters to all other species. The Eurasian crested titmice (subgenus Lophophanes) and North American crested titmice (subgenus Baeolophus) are sister groups. Our data suggest two colonizations of the New World by parids in the late Tertiary. The ancestor of modern Baeolophus colonized North America 4 mya, and the ancestor of all North American chickadees colonized North America 3.5 mya.Phylogénie chez la mésange (Paridés): II. Relations entre les espèces basées sur des séquences du gène mitochondrial cytochrome-b

PHYLOGENY OF TITMICE (PARIDAE): II. SPECIES RELATIONSHIPS BASED ON SEQUENCES OF THE MITOCHONDRIAL CYTOCHROME-B GENE

We present a phylogenetic hypothesis for 40 species in the bird family Paridae, based on comparisons of nucleotide sequences of the mitochondrial cytochrome-b gene. Parids, including tits and chickadees, are an older group than their morphological stereotypy suggests. The longest cytochrome-b distances between species reach 12% in uncorrected divergence. With the exception of one thrasher-like terrestrial tit species of the Tibetan plateau (Pseudopodoces humilis), morphological and ecological stasis have prevailed since the initial parid radiation in the Old World during the mid-Tertiary. All trees support monophyly of the family Paridae, which includes Parus (sensu lato) and the monotypic Oriental genera Sylviparus, Melanochlora, and Pseudopodoces. Within the clade of chickadees and gray tits (Parus, subgenus Poecile), three Old World species, Parus lugubris of the eastern Mediterranean and Balkan regions, P. superciliosus of high elevations in the Himalayas of western China, and P. varius of the Orient are sisters to all other species. The Eurasian crested titmice (subgenus Lophophanes) and North American crested titmice (subgenus Baeolophus) are sister groups. Our data suggest two colonizations of the New World by parids in the late Tertiary. The ancestor of modern Baeolophus colonized North America 4 mya, and the ancestor of all North American chickadees colonized North America 3.5 mya. Phylogénie chez la mésange (Paridés): II. Relations entre les espèces basées sur des séquences du gène mitochondrial cytochrome-b

Possible roles of habitat, competition and avian nest predation in the decline of the Willow Tit Parus montanus in Britain

Capsule Although stable in their preferred, wet habitats, Willow Tits have declined in woodland, probably because of habitat degradation rather than increases in avian nest predator and competitor numbers. Aims To elucidate the cause of the population decline by investigating variations with habitat and testing the hypothesis that an increase in nest predators or competitors (especially for nest-holes) could be responsible. Methods I analysed with respect to survey plot habitat over 30 years of Willow Tit abundance data from a national survey. I examined the relationships with the local abundance of key potential nest predators (woodpeckers and Jay Garrulus glandarius) and key potential competitors (other tit species and Nuthatch Sitta europaea). Results Willow Tits have declined in farmland and woodland in Britain, but not in their preferred, wet habitats. There was no evidence for any negative effect of competition and the only potentially important negative correlation with the abundance of a predator (Great Spotted Woodpecker Dendrocopus major) was limited to farmland, a relatively minor habitat. A negative relationship with Green Woodpecker Picus viridis probably reflects opposite habitat preferences. Conclusions Although correlative studies of competition and predation cannot be definitive, the evidence of this study suggests that the major cause of the Willow Tit's decline in Britain is habitat degradation, especially in woodland. Possible mechanisms for this degradation are discussed.

Effect of Daily Body Mass Variation on the Foraging Behaviour of Tit Species (Parus spp.)

AbstractWe studied the effect of daily body mass increase on the foraging preferences of two tit species, crested tit, Parus cristatus and blue tit, P. caeruleus, contrasting in morphology and behaviour. We found that both species show a diurnal increase in body mass during winter. Using an experiment with feeders we show that in the crested tit, the proportion of time spent foraging while hanging decreased as body mass increased. In contrast, in the blue tit, foraging behaviour did not change with mass gain. We propose that the species with a morphological design providing a high ecological plasticity in terms of foraging postures can counteract the negative effect of body mass on the ecological options (foraging niche) more than species with a morphological design providing a low ecological plasticity in terms of foraging postures. Our results suggest that blue tits had the advantage of being able to choose to feed on different patches in the habitat throughout the day, which makes resources more predictable for them. In contrast, crested tits might be more restricted in their foraging options as their body mass increases, and this might explain why they hoard food.

Mate choice and imprinting in birds studied by cross-fostering in the wild.

Sexual-selection theories generally assume that mating preferences are heritable traits. However, there is substantial evidence that the rearing environment may be important for the development of mating preferences, indicating that they may be learnt, or modified by experience. The relative importance of such sexual imprinting across species remains largely unexplored. Here, we report results of a large-scale cross-fostering experiment in the wild in which nestling birds were raised by parents of a different species. We show that resulting sexual imprinting may have a negative effect on pairing success in one species (the great tit, Parus major), but not in two other species (the blue tit, P. caeruleus and the pied flycatcher, Ficedula hypoleuca). A remarkable variation thus seems to exist, even between species that are congeneric and have similar breeding ecologies. The cross-fostering resulted in heterospecific pairings between the two tit species (female blue tit breeding with male great tit), which has never, to our knowledge, been previously documented. However, the chicks fledging from these nests were all blue tit.

Prey distribution and foraging preference for tits

We examined the abundance and distribution of prey in four different height strata and eight tree species in a temperate forest, and analyzed the influence on foraging preference by three breeding tit (Parus) species. Densities of arthropod prey for tits in canopy foliage varied with tree species but not with height. Most of them were Lepidoptera larvae. Also, interspecific differences in choice of foraging substrate were found between tree species but not in height. These results demonstrate that tree species composition is a more important habitat factor than foliage height profile for coexistence of different tit species in forests. We examined four different measures of prey abundance to find how tits chose tree species. The largest species, the Great Tit P. major, preferred the tree species with high total biomass, and the intermediate-sized Willow Tit P. montanus preferred those with high density per leaf area. Concentrated searching for prey on a few tree species with high total biomass may be a useful strategy for inflexible perch-gleaners such as P. major, and finer-scale searching on each leaf may be more practical for agile foragers such as P. montanus which often hang-glean to reach less accessible food. In spite of these differences, both species gained benefits from choosing the tree species on which they foraged most efficiently. In contrast, the smallest species, the Coal Tit P. ater, frequently foraged on food-poor tree species. Of the three tit species, P. ater was the most generalized forager, using diverse techniques on a variety of tree species and specializing at capturing small prey quickly. These foraging patterns may make it possible for the smallest species to coexist with the other tit species.

Modeling large-scale dispersal distances

We present an approach to analyze dispersal distance data. This approach allows one to take into account accuracy of the recorded dispersal distances. Three distributions were used, all assuming continuous space; a maximum likelihood approach was used for parameter estimation and model selection. Numerical simulations showed that our method is statistically consistent since it selected the correct model with increasing frequency when sample size increased. Ringing data on two species of tits ( Parus caeruleus and Parus major) in Britain and Ireland were used to illustrate the potentialities of our method. In both species, adults dispersed significantly further than juveniles. The differences between species within an age-class were not statistically significant. In all species and age-classes, the model finally selected was the one assuming a heavy-tailed half-Cauchy distribution where long-distance dispersers are predicted to be more frequent than in the exponential model. The proposed methodology can potentially be applied to any organisms, and the model selection procedure can be used with any model of the distribution of dispersal distances (DDD). Several extensions are presented in the discussion, such as generalized linear modeling of the dispersal parameters, or interfacing with capture–recapture models.

The effects of food availability and distance to protective cover on the winter foraging behaviour of tits (Aves: Parus).

To maximize fitness, many animals must trade off their need to forage efficiently against their need to avoid predators. We studied such a trade-off in four species of tits (Paridae) in a forest near Oxford, UK. During winter, tits form flocks which increase feeding efficiency and reduce predation risk. These flocks feed extensively on beech (Fagus sylvatica) seeds, the abundance of which may be critical for winter survival. Because these seeds drop to the ground, where birds are exposed to sparrowhawk (Accipiter nisus) attack, tits need to trade off their need to find seeds against the proximity to protective cover, provided by dense clusters of hawthorn (Crataegus spp.). The quality of the beech crop differs markedly between trees and years. During a year of abundant beechmast, most tits searched for seeds close to protective cover. This 'safety-first' strategy precluded visits to superabundant food patches if they were too far from protective cover. Among beech trees near to cover, tits tended to prefer those with high seed density. Tits benefited from foraging under trees with high seed density because this correlated significantly with seed mass per square metre and because mean search times decreased with increasing seed density. Finally, we show experimentally that great tits, Parus major, can discriminate between edible (viable) and inedible (empty) seeds.

Ecological plasticity by morphological design reduces costs of subordination: influence on species distribution.

We studied the feeding behaviour of two subordinate tit species (Parus spp.) in two competitive contexts: feeding solitarily versus feeding in the presence of the dominant great tit. Considering ecological plasticity as the within-species component of mean behavioural performance associated with different morphologies in different species, we test the hypothesis that subordinate species with morphological designs allowing a greater ecological plasticity (e.g. blue tit whose hindlimb morphology is modified for greater leg flexion) may gain an advantage against subordinate species with a less plastic design (e.g. crested tit whose hindlimb morphology is modified for aid in leg extension) in a competitive context. Our results demonstrate that the blue tit has greater foraging abilities than the crested tit, as the former is able to modify its feeding behaviour in the presence of the dominant great tit significantly more than the crested tit. In light of these results we propose that some subordinate species can take advantage of their greater ecological plasticity against another less plastic, subordinate species, suggesting that ecological plasticity due to morphological design is a way of reducing costs of subordination as well as a novel, alternative mechanism explaining species distribution.

Factors Influencing Pair Territoriality in the Juniper Titmouse

Abstract Pair territoriality outside of the breeding season is a relatively uncommon pattern of social organization in the Paridae (tits, titmice, and chickadees). Within the territorial parids, pair territoriality appears to be the derived state. Because of this, it is possible to address the question: What favors the evolution of this social system? I assessed factors that may be responsible for inducing pair territoriality in Juniper Titmice (Baeolophus ridgwayi), focusing largely on foraging behavior and predation risk. I found that the diet of Juniper Titmice is distinctive as compared to other tits, with large seeds (juniper and pinyon pine) and acorns making up most of the winter diet instead of arthropods. Time budgets reflected that a large proportion of time is spent handling food. Space use was strongly skewed toward locations that should be relatively safe from predators, both because food is located in such sites and because titmice transport seeds to sheltered sites for processing. Seeds decreased significantly in abundance through the course of the winter. Comparisons with group-living tit species that forage largely on arthropods show differences in time and space use. I conclude that the suite of behaviors associated with foraging on large seeds has shifted the cost-to-benefit ratio of group living for Juniper Titmice relative to other tits.

Fat reserves and perceived predation risk in the great tit, Parus major.

The fat reserves of small birds are built up daily as insurance against starvation. They are believed to reflect a trade-off between the risks of starvation and predation such that in situations of high predation risk birds are expected either to reduce their fat reserves in response to mass-dependent predation risk or to increase them in response to foraging interruptions. We assessed the effect on fat reserves of experimentally altering the perceived (but not the actual) risk of predation of wild great tits at a winter feeding site. The perceived predation risk was alternated between 'safe' and 'risky'. Increasing the perceived risk of predation involved 'swooping' a model sparrowhawk over the feeder at four unpredictable times each day using a remote mechanism We produce evidence that the experiment was suceessfull in altering the perceived risk of predation. As predicted from the hypothesis of mass-dependent predation risk, great tits (Parus major) carried significantly reduced fat reserves during the 'risky' treatment. Furthermore, dominant individuals were able to reduce their reserves more than subordinates. As birds returned to feeders within seconds after a predator 'attack', the reduction in fat reserves cannot be attributed to an interruption in feeding.

The Role of Search Area in the Detection of Cryptic Prey by Crested Tits and Coal Tits

The probability of perception of prey may depend on the previous experience of the predator, its expectations and its search tactics. In this study we investigated the role of the search area. Based on previous results and on known facts about foraging ecology, we hypothesised that crested tits ( Parus cristatus ) would perform better when searching larger areas for cryptic prey compared with coal tits ( Parus ater ) that have been found to search small areas for cryptic prey more successfully. In our experiments these two tit species were required to search for cryptic prey in large and small dishes. Both species detected cryptic prey less frequently in the larger dishes, however, crested tits performed better initially. Coal tits improved over time. Both species needed more time for detecting prey in large dishes, and crested tits searched longer in small dishes than coal tits. Giving-up times, when no prey was found, also reflected these differences. The results suggest that the tits search with speciesspecifically set search areas and 'time windows'. It also appeared that coal tits are more flexible in adjusting search to a given situation.

Individual food-hoarding decisions in a nonterritorial coal tit population: the role of social context

Among the Paridae, food hoarding is thought to be strongly associated with the exclusive use of territories by winter groups, although it has also been described in populations with loose social systems. However, detailed data on such populations are scarce. To identify the mechanisms underlying individual storing decisions, I studied hoarding behaviour in a nonterritorial, high-density coal tit, Parus ater, population in a subalpine forest. The presence of close neighbours (within 5m) had the strongest, negative influence on caching probability, whereas more distant neighbours foraging in the same flock did not affect the probability of caching. Adults concentrated their stores in the centre of their home ranges. Caching location, but not caching intensity, was affected by the time of day. Coal tits took longer, and travelled further, to cache food in the inner parts of trees than in the outer parts. Resident adults stored in inner, safer caching locations more often than juvenile residents and transients. Differences in hoarding effort according to the storing substrate, and the daily storing location pattern of juvenile residents and transients, suggest that stores have a different use depending on where they are located. Therefore, my results show that hoarding is compatible with a nonterritorial, nonbreeding social system; hoarding could thus have originated in an ancient, nonterritorial, but sedentary, tit species.

Density dependence of avian clutch size in resident and migrant species: is there a constraint on the predictability of competitor density?

The presence of density dependence of clutch size is tested in 57 long‐term population studies of 10 passerine bird species. In about half of the studies of tit species Parus spp. density dependence of clutch size was found, while none was found in studies of two flycatcher species Ficedula spp. One hypothesis explaining this difference is that migrants are less able to predict the final competitor density, because new pairs are still settling when the first females start laying eggs. Such unpredictability is only a problem for early laying females. If this explanation is true, the commonly observed negative correlation between clutch size and laying date should be stronger in high‐density years. I tested this prediction in three populations of Pied Flycatcher Ficedula hypoleuca, and compared the results with three populations of Great Tit Parus major. In none of the six populations was there a significant correlation between the strength of the seasonal decline in clutch size and population density. Thus the lack of density dependence of clutch size in Pied Flycatchers was not consistent with the idea that this is caused by the unpredictability of final density at the time of egg‐laying of the earliest females in the population. Furthermore, density does not have any adverse effect on reproductive output of Pied Flycatchers, and therefore they do not adjust clutch size to density.

Host specificity in avian blood parasites: a study of Plasmodium and Haemoproteus mitochondrial DNA amplified from birds.

A fragment of the mitochondrial cytochrome b gene of avian malaria (genera Haemoproteus and Plasmodium) was amplified from blood samples of 12 species of passerine birds from the genera Acrocephalus, Phylloscopus and Parus. By sequencing 478 nucleotides of the obtained fragments, we found 17 different mitochondrial haplotypes of Haemoproteus or Plasmodium among the 12 bird species investigated. Only one out of the 17 haplotypes was found in more than one host species, this exception being a haplotype detected in both blue tits (Parus caeruleus) and great tits (Parus major). The phylogenetic tree which was constructed grouped the sequences into two clades, most probably representing Haemoproteus and Plasmodium, respectively. We found two to four different parasite mitochondrial DNA (mtDNA) haplotypes in four bird species. The phylogenetic tree obtained from the mtDNA of the parasites matched the phylogenetic tree of the bird hosts poorly. For example, the two tit species and the willow warbler (Phylloscopus trochilus) carried parasites differing by only 0.6% sequence divergence, suggesting that Haemoproteus shift both between species within the same genus and also between species in different families. Hence, host shifts seem to have occurred repeatedly in this parasite host system. We discuss this in terms of the possible evolutionary consequences for these bird species.

Does predation maintain tit community diversity?

European tits of the genus Parus constitute a complex group of coexisting boreal birds. Here we present a survey of the distribution of three coniferous‐living Parus species and one of their main predators, the pygmy owl (Glaucidium passerinum), on nine isolated islands in Scandinavia. On all islands the coal tit (Parus ater) is the sole tit species when the pygmy owl is absent. The two larger species, the willow tit (P. montanus) and the crested tit (P. cristatus), only coexist with the coal tit when pygmy owls are present. We suggest that the coexistence of willow tits, crested tits and coal tits is the result of a combination of competition for food and predator‐safe foraging sites. The smaller coal tit is superior in exploitation competition for food, while the two larger species have an advantage in interference competition for predator‐safe foraging sites. The association between the distribution of the pygmy owl and the two larger tit species on isolated islands in Scandinavia is consistent with the idea that the pygmy owl is a keystone predator.

Timing of breeding in subarctic passerines in relation to food availability

We studied timing of breeding in four species of hole-nesting passerines, the Siberian tit (Poecile cinctus), great tit (Parus major), pied flycatcher (Ficedula hypoleuca), and redstart (Phoenicurus phoenicurus), and the abundance of the arthropods in their diet (ground-dwelling spiders, winged insects, foliage-feeding lepidopteran and hymenopteran larvae) in Finnish Lapland for 6-12 years. Densities of the invertebrate groups varied considerably, both seasonally and annually. All the bird species started to breed in early summer, when weather conditions were often poor. At the beginning of the breeding season all species relied on ground-dwelling spiders, whose abundances peaked early and were less variable over the years than those of insects. Abundances and timing of emergence of caterpillars in birch and pine canopies (the major food sources for foliage-gleaners) were highly variable, but each year their abundances peaked in July or August, after the nestling period of the birds. This contrasts with reported cases in deciduous forests at midlatitudes and shows that at our site the birds did not time their nestling period ultimately to coincide with peak food availability. Mean clutch sizes declined seasonally in the tit species and the pied flycatcher but not in the redstart. The number of fledglings did not depend on laying date, except in the Siberian tit, for which dependence of fledgling number on laying date varied among years. Although early broods were not more productive (i.e., greater number of fledglings) than later ones, early breeding is ultimately a necessity for recruitment because of the short subarctic summer. Birds cannot delay breeding in the north because late breeding would shorten the time available for moulting, food-hoarding, and preparation for migration or wintering. Our results show that at the time of egg laying, passerines may receive proximate cues to allow them to predict food conditions during the nestling period. Still, exact prediction of food availability during later phases of nesting is constrained by an inherent discrepancy between warm-blooded birds and poikilothermic invertebrates: once a bird has started egg laying, the subsequent phases follow nearly automatically on certain calendar dates, whereas the development of the arthropods depends on the rate of temperature increase.