Blue Chaffinch Research Articles

Establishment success of the reinforced population of Gran Canaria Blue Chaffinch Fringilla polatzeki

The Gran Canaria Blue Chaffinch is the rarest forest passerine in the western Palaearctic with a population reduced to a single locality, Inagua, in the west of the island. After a forest fire, some birds were established in another location and a reinforcement programme was launched with the aim of consolidating this new population. Between 2010 and 2019, 194 Blue Chaffinches were released in the pine forest of La Cumbre, in the centre of the island and at a higher altitude than the previous one. Birds of two origins were used for this action: captive-bred birds were released using “soft” release methods, and wild-caught birds from the Inagua source population were released using “hard” release methods. Survival of radio-tagged birds (20–42 days of battery life) was high and similar between the two groups. Wild-caught birds occupied 12–15 times more surface area than captive-bred birds that remained close to supplementary feeding sites. All translocated birds displayed breeding behaviour in the following breeding season, although the rate of contribution to the new population was significantly lower for wild-caught birds (21% compared to 54% for captive-bred birds). This disparity can be partly attributed to nearly one-fifth of the wild-caught birds returning to Inagua. We conclude that the establishment phase of the Blue Chaffinch reinforced program in Gran Canaria has been successful. To retain wild-caught birds and deter their return to the source population, we recommend employing methods akin to the soft-release techniques utilized for captive-bred birds. Ongoing monitoring of the enhanced population, collecting data on survival and breeding success, will enable the evaluation of the long-term success of the translocation program.

The complete mitochondrial genome of the Brambling Fringilla montifringilla (Passeriformes: Fringillidae) from Maor Mountain, China

The Brambling (Fringilla montifringilla) (Linnaeus 1758) is a member of the Passeriformes family of birds and primarily feeds on grass seeds and grains. Muscle tissue was collected from birds sampled from Moar Mountain, China, and the complete mitochondrial genome was sequenced. Its mitochondrial genome consists of 13 protein-coding genes (PCGs), 2 rRNA genes (12S rRNA and 16S rRNA), 22 tRNA genes, and 1 control region (CR). The genome comprises 30.30% A, 23.32% T, 14.31% G, and 32.07% C bases. Phylogenetically, F. montifringilla is closely related to the Fringilla coelebs, Fringilla teydea teydea and Fringilla polatzeki.

Population size, abundance, habitat relationships and the result of a translocation programme in the Gran Canaria Blue ChaffinchFringilla polatzeki

SummaryThe Gran Canaria Blue ChaffinchFringilla polatzekiis a threatened, endemic, forest‐dwelling bird species of the Canary Islands, whose core population at the end of the 20th century was restricted to the pine forests of Inagua Nature Reserve (38 km2). A translocation programme released birds from a breeding centre into the nearby (<3 km) pine forests of La Cumbre in the years following 2010. From 2015 to 2019 the La Cumbre population was reinforced by translocation of wild juveniles from the source population of Inagua. We estimate the population size, the spatial variation of abundance, and recent temporal changes in density of the species in Inagua and La Cumbre by means of line transects, distance sampling, and habitat suitability modelling using random forests. The average density of the Blue Chaffinch in Inagua Nature Reserve was 10.2 birds/km2in spring 2019, with a population estimated at 362 birds (95% CI: 257–489). The most important variables affecting the distribution of the Blue Chaffinch in Inagua were the amount of precipitation during the summer (July–September), the solar radiation in June, and the northern position in the reserve, highlighting the importance of abiotic factors related to thermal and hydric stress during the breeding season. The density was considerably lower in the translocated population inhabiting 21 km2of pine forests in La Cumbre (3.3 birds/km2), with an estimate of 68 Blue Chaffinches (35–141) breeding freely in the wild. The translocation programme successfully contributed to the establishment of a second viable nucleus, accounting for 16% of the total population within a time span of 10 years. This result reinforces the role of translocations in preventing extinctions of endangered species with very low population sizes restricted to only one isolated area.

Striking resilience of an island endemic bird to a severe perturbation: the case of the Gran Canaria blue chaffinch

espanolSon pocos los datos disponibles sobre la tendencia demografica de las especies en peligro de extincion en zonas de proteccion especial y su capacidad de recuperarse de perturbaciones catastroficas. Se estudia la tendencia demografica del pinzon azul de Gran Canaria (Fringilla polatzeki), un especialista de habitat endemico de las Islas Canarias, restringido al pinar de Inagua, que sufrio un devastador incendio forestal en julio de 2007. Mediante un programa de censo estandarizado que tiene en cuenta la variacion en la capacidad de deteccion, se ha hecho un seguimiento de la tendencia demografica de la especie desde la declaracion de Inagua como reserva natural integral en 1994. La densidad reproductiva del pinzon azul se mantuvo estable en Inagua desde el inicio del programa de seguimiento en 1994 hasta un ano antes del incendio. No obstante, en la primavera de 2008, la densidad de la poblacion se redujo a la mitad en comparacion con los anos anteriores. A partir de 2008, la poblacion del pinzon azul ha venido aumentando gradualmente hasta alcanzar la densidad mas alta jamas registrada en 2016 (15,8 aves/km2), lo que equivale a un incremento anual medio del 23,7% y pone de manifiesto la resistencia impresionante de estas poblaciones ante catastrofes. Por lo tanto, la creacion de la reserva integral de Inagua no promovio el aumento de poblacion ni protegio al pinzon azul frente a una grave crisis demografica, sino que probablemente evito que la disminucion de la poblacion fuera mas profunda o que se produjeran otras reducciones. Aparte de los dos anos inmediatamente posteriores al incendio forestal de 2007, la densidad de poblacion del pinzon azul en Inagua se mantuvo relativamente estable alrededor de 9–16 aves/km2, la menor abundancia jamas registrada para un paseriforme forestal de tamano pequeno en todo el paleartico occidental. EnglishEvidence regarding population trends of endangered species in special protection areas and their recovery ability from catastrophic disturbances is scarce. We assessed the population trend of the Gran Canaria blue chaffinch (Fringilla polatzeki), a habitat specialist endemic to the pine forest of Inagua in the Canary Islands, following a devastating wildfire in July 2007. Using a standardized census program that accounts for detectability, we have monitored the population trend of the species since Inagua was declared a Strict Nature Reserve in 1994. The breeding population density of the blue chaffinch remained stable in Inagua from the beginning of the monitoring program in 1994 until the year before the wildfire. However, in spring 2008, the population density decreased by half with respect to density in the preceding years. Since 2008, the population has gradually increased, reaching its highest recorded density in 2016 (15.8 birds/km2).This represents an average annual increase of 23.7%, indicating impressive resilience to catastrophic events. The creation of Inagua as a strict nature reserve did not therefore increase the global population or protect the blue chaffinch against a demographic crisis but probably prevented a deepening of the demographic crisis or further declines. Except for the two years immediately after the severe wildfire of 2007, the population density of the blue chaffinch in Inagua has remained relatively stable at around 9–16 birds/km2, the lowest recorded abundance for a small woodland passerine in the Western Palearctic.

Habitat suitability-density relationship in an endangered woodland species: the case of the Blue Chaffinch (Fringilla polatzeki).

BackgroundUnderstanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs.MethodsWe studied the Gran Canaria blue chaffinch (Fringilla polatzeki), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994.ResultsThe variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July–September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195–430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic.DiscussionHabitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.

Species-level divergences in multiple functional traits between the two endemic subspecies of Blue Chaffinches Fringilla teydea in Canary Islands

One of the biggest challenges in avian taxonomy is the delimitation of allopatric species because their reproductive incompatibility cannot be directly studied in the wild. Instead, reproductive incompatibility has to be inferred from multiple, divergent character sets that indicate a low likelihood of allopatric populations amalgamating upon secondary contact. A set of quantitative criteria for species delimitation has been developed for avian taxonomy. Here, we report a broad multi-trait comparison of the two insular subspecies of the Blue Chaffinch Fringilla teydea, endemic to the pine forests of Tenerife (ssp. teydea) and Gran Canaria (ssp. polatzeki) in the Canary Islands. We found that the two taxa were reciprocally monophyletic in their whole mitogenomes and two Z chromosome introns. The genetic distance in mitogenomes indicates around 1 Mya of allopatric evolution. There were diagnostic differences in body morphometrics, song and plumage reflectance spectra, whose combined divergence score (=11) exceeds the threshold level (=7) set for species delimitation by Tobias et al. (Ibis 152:724–746, 2010). Moreover, we found a marked divergence in sperm lengths with little range overlap. Relatively long sperm with low intra- and intermale CV compared to other passerines suggest a mating system with high levels of sperm competition (extrapair paternity) in these taxa. The large and diagnostic divergences in multiple functional traits qualify for species rank, i.e., Tenerife Blue Chaffinch (Fringilla teydea) and Gran Canaria Blue Chaffinch (Fringilla polatzeki). We encourage a wider use of sperm traits in avian taxonomy because sperm divergences might signal reproductive incompatibility at the postcopulatory prezygotic stage, especially in species with sperm competition.

Integrative taxonomy reveals Europe's rarest songbird species, the Gran Canaria blue chaffinchFringilla polatzeki

The conservation of endangered taxa often critically depends on accurate taxonomic designations. The status of the Gran Canaria population of the blue chaffinchFringilla teydea polatzekihas not been reevaluated since the early 1900s when this taxon was described as a subspecies and combined with the much more common Tenerife blue chaffinchF. t. teydeain a single species. We show that multiple diagnostic differences in plumage, songs, calls and morphometrics distinguishF. t. polatzekifromF. t. teydea. Preliminary playback experiments suggest thatF. t. polatzekiis able to discriminate between songs of both taxa. Along with previously reported differences in mitochondrial DNA, these findings show that the blue chaffinches on Gran Canaria and Tenerife represent two distinctive species:F. polatzekiandF. teydea. Gran Canaria blue chaffinch is Europe's rarest passerine species and should be classified as critically endangered. Its long‐term survival in the wild currently depends on a very small (< 20 km2) area in southwest Gran Canaria. Reclassification of Gran Canaria blue chaffinch as a species increases the urgency of ongoing conservation efforts. Our study underscores the critical importance of taxonomic clarification of threatened taxa that are currently classified as ‘subspecies’.

Reduced genetic diversity and sperm motility in the endangered Gran Canaria Blue Chaffinch Fringilla teydea polatzeki

The Blue Chaffinch (Fringilla teydea) is endemic to the Canary Islands and restricted to the pine forests on Tenerife (ssp. teydea) and Gran Canaria (ssp. polatzeki). While the teydea population is large and stable, the polatzeki population underwent a dramatic decline in the twentieth century and currently numbers less than 200 individuals. Here, we show that microsatellite allelic diversity is lower in polatzeki than in teydea, consistent with a genetic bottleneck scenario. Our genotyped polatzeki individuals, which were wild-caught but currently used in a captive breeding programme, have the same allelic diversity as free-ranging birds. However, the captive polatzeki males seem to have reduced sperm motility as compared with captive teydea males, which could be an effect of reduced genetic diversity. Because polatzeki and teydea are phylogenetically distinct, they should be recognized as Evolutionarily Significant Units by conservation authorities. We also recommend maintaining the captive polatzeki population as a pre-emptive measure against extinction in the wild.

Genetic signature of a severe forest fire on the endangered Gran Canaria blue chaffinch (Fringilla teydea polatzeki)

Habitat destruction has been identified as one of the main threats to biodiversity. Among all factors causing habitat disturbance, wildfire is recognized as one of the most important ecological forces that influences not only the physical environment, but also the structure and composition of floral and faunal communities. These processes are often translated in population bottlenecks, which occur frequently in threatened species and result in loss of genetic diversity and evolutionary potential. In this study, we analyzed the genetic consequences of a demographic bottleneck produced by a forest fire that reduced the population of the endangered blue chaffinch (Fringilla teydea polatzeki), which inhabits the island of Gran Canaria, to approximately 122 individuals. Analysis of nine microsatellite loci revealed that, while a decline in census was observed during the bottleneck, there was no observed excess of heterozygosity or evidence of a decline in allelic richness, two characteristic bottleneck signatures. On the contrary, we observed that the Gran Canaria blue chaffinch has retained significant levels of genetic diversity and shows no evidence of an increased level of inbreeding (FIS) either before or after the bottleneck. The results from this study have important implications for the conservation of this endangered subspecies and provide insights concerning management strategies to prevent its extinction.

Medium-term response of breeding Blue Chaffinch Fringilla teydea teydea to experimental thinning in a Pinus canariensis plantation (Tenerife, Canary Islands)

We studied the medium-term response of the endemic Blue Chaffinch Fringilla teydea teydea to experimental thinning in a Pinus canariensis plantation on the island of Tenerife during breeding season. Distance Sampling method was applied to line transects, and habitat preferences were modelled by means of univariate regression trees. The density was 1.70 birds/ha (1.09 to 2.68 95%CI) in thinned areas and 0.56 birds/ha (0.33 to 0.97 95%CI) in unthinned areas. The Blue Chaffinch densities peaked in thinned areas where the density of trees with Diameter at Breast Height of

Spatiotemporal variation of a Pinus seed rain available for an endemic finch in an insular environment

A major goal of avian ecological research is to determine how distribution and abundance of preferred resources available influence population dynamics and contribute to understand life-history characteristics. Food is widely considered the ultimate factor influencing these traits. We studied, with seed traps, the spatiotemporal variability of Pinus canariensis seed rain during 2007–2008, as a means to explain why a post-dispersal seed predator of conservation concern, the endemic blue chaffinch Fringilla teydea, can adjust its annual life cycle with this variation in an insular environment. Generalized linear mixed models and geostatistical tools were used. Results highlight that temperature and relative humidity are important predictors of seed release rates. Additionally, a high temporal variation was detected in seed abundance (i.e., peaks of massive seed release during the summer months, intermediate values in the autumn, and minimum release rates in winter and spring). Finally, within-stand spatial variation in seed flux was surprisingly large with the most productive microsites receiving three to four times more seeds than the least productive ones. Pine seeds showed a high protein value and a low germination rate. Based on these findings, we suggest that the fortunes of the blue chaffinch should be intimately related to spatiotemporal annual P. canariensis seed crops, temperature acting as a proximate cue, and food availability as the ultimate factor. For the endangered blue chaffinch population on Gran Canaria, we recommend, until more data are available, improving the seed supply during the winter season, either artificially (feeders) or naturally (planting Myrica faya shrubs).

Disentangling Ancient Interactions: A New Extinct Passerine Provides Insights on Character Displacement among Extinct and Extant Island Finches

BackgroundEvolutionary studies of insular biotas are based mainly on extant taxa, although such biotas represent artificial subsets of original faunas because of human-caused extinctions of indigenous species augmented by introduced exotic taxa. This makes it difficult to obtain a full understanding of the history of ecological interactions between extant sympatric species. Morphological bill variation of Fringilla coelebs and F. teydea (common and blue chaffinches) has been previously studied in the North Atlantic Macaronesian archipelagos. Character displacement between both species has been argued to explain bill sizes in sympatry. However, this explanation is incomplete, as similar patterns of bill size have been recorded in F. coelebs populations from islands with and without F. teydea.Methodology/Principal FindingsThe discovery of a new extinct species in Tenerife (Canary Islands), here named Carduelis aurelioi n. sp. (slender-billed greenfinch), provides the opportunity to study ancient ecological interactions among Macaronesian finches. To help understand the evolutionary histories of forest granivores in space and time, we have performed a multidisciplinary study combining: (1) morphological analyses and radiocarbon dating (11,460±60 yr BP) of the new taxon and, (2) molecular divergence among the extant finch species and populations in order to infer colonization times (1.99 and 1.09 My for F. teydea and F. coelebs respectively).Conclusion/Significance C. aurelioi, F. coelebs and F. teydea co-habited in Tenerife for at least one million years. The unique anatomical trends of the new species, namely chaffinch-like beak and modified hind and forelimbs, reveal that there was a process of divergence of resource competition traits among the three sympatric finches. The results of our study, combined with the presence of more extinct greenfinches in other Macaronesian islands with significant variation in their beak sizes, suggests that the character displacement has influenced patterns of divergence in bill size and shape on other Macaronesian islands as well.

Effects of wildfire on endemic breeding birds in a Pinus canariensis forest of Tenerife, Canary Islands

Fire is a key ecological force in pine forests worldwide, and faunal responses to this disturbance have been a major topic of ecology, yet little is known for oceanic island environments. Using line transects we surveyed the bird community of a natural Pinus canariensis forest burned in the summer of 2007 on Tenerife, Canary Islands, Spain. Our goal was to identify important environmental variables and the thresholds that influenced the pattern of bird abundance at the community, foraging guild, and species-specific level. Models were constructed by means of regression trees and cross validation applying the 1-SE rule. Mixed results were observed and only 2 species were clearly affected by fire severity. Overall, total bird abundance, total species richness, and total bird diversity were positively influenced by low, very low, and moderate canopy fire severity, respectively, and the presence of either Erica or Myrica shrubs. Consequently, high canopy fire severity had an overall negative effect on bird community characteristics. Abundance of Myrica shrubs affected positively general ground foragers such as common blackbird (Turdus merula cabrerae) and Canary Islands chiffchaff (Phylloscopus canariensis), a canopy forager. The number of thin trees was important for canopy foragers such as goldcrest (Regulus regulus teneriffae) and African blue tit (Cyanistes teneriffae teneriffae), but also for a bark forager, the great spotted woodpecker (Dendrocopos major canariensis). European robin (Erithacus rubecula superbus) and the ubiquitous endemic blue chaffinch (Fringilla teydea teydea) were influenced by low and moderate canopy fire severity, respectively. We recommend that land managers incorporate these results into future post-fire management plans. Priority post-fire actions should be directed toward the protection and conservation of the endemic blue chaffinch, a species of conservation concern on the nearby island of Gran Canaria.

Habitat characteristics and seed crops used by Blue Chaffinches Fringilla teydea in winter: implications for conservation management

Capsule Tree cover and seeds on the ground influence the occurrence of Blue Chaffinches during the non‐breeding period. Aims To study the feeding habitat selection of the common Tenerife Blue Chaffinch race during the non‐breeding period as a desperate measure to conserve the endangered Gran Canaria race, whose critical area was burnt in the summer of 2007. Methods Basic statistics were used to test for differences between occupied sites (n = 35) and available representative sites (n = 35). Univariate classification tree models were applied to explore the relationship between a single response variable (presence–absence) and multiple explanatory variables and the relative importance of these. Pine seed availability was quantified on the trees (n = 70) and on the ground (n = 140; 1 × 1 m plots). Results We found a non‐random feeding habitat selection by Blue Chaffinches on Tenerife. During the non‐breeding period Blue Chaffinches selected those areas for feeding on pine seeds where the tree cover was higher than 38% (mature areas with tall and thick trees with good crops). When the tree cover was lower than 38%, the mean number of seeds on the ground influenced the presence of this finch (> 0.05 seeds per m2). Conclusions This study highlights that Blue Chaffinches primarily select sheltered sites for feeding during the non‐breeding period. The selection of less sheltered sites seems to be mediated by pine seed availability. Therefore, in this endemic forest system, perceived predation risk, food abundance and availability, and overall availability of safe foraging options are all possibly determining the winter feeding habitat selection. We recommend selective cuts in high‐density pine stands to recreate those conditions that allow the pine trees to set seed and management aimed at creating a structure of dispersed small‐area compartments with mature trees that provide food and shelter. The installation of artificial feeders seems to be a post‐fire priority action for the conservation of the Gran Canaria race.

Breeding Biology of the Endangered Blue ChaffinchFringilla Teydea Polatzekiin Gran Canaria (Canary Islands)

The Blue Chaffinch is a passerine endemic to the Canary Islands and comprises two subspecies, one found on Tenerife (Fringilla teydea teydea) and the other on Gran Canaria (F. t. polatzeki). Even though the status of the Gran Canaria subspecies is endangered due to habitat loss and fragmentation, knowledge of its life history is anecdotal. We studied its breeding ecology during the years 1991–2004. New data are presented on breeding phenology, number of broods per year, egg biometrics, nest-site characteristics, breeding site fidelity and breeding success. In general, the breeding biology of the two subspecies were similar, with discrepancies in some previously reported traits, such as egg laying interval and frequency of second clutches. The Blue Chaffinch breeds earlier on Gran Canaria than on Tenerife: nests were begun mainly in the second fortnight of May. We did not find any relationship between the onset of egg laying and rainfall in March. However, the onset of the breeding period was negatively correlated with mean April temperature. The Blue Chaffinch showed preferences for a south-easterly nest orientation and for nest placement at the end of branches, where the nest is hidden by pine needles. Nests were located at various heights, from 5.5 to 23.8 m above the ground. 33% of females produced two broods a year. We found no differences in nest site characteristics between successful and unsuccessful nests, which suggests that other factors may be affecting the vulnerability of nests. The main cause of nesting failure (73.9%) was predation, due mostly to the Great Spotted Woodpecker.

Microsatellite loci isolation in the endangered Gran Canarian blue chaffinch (Fringilla teydea polatzeki) and their utility in closely related taxa

The blue chaffinch, Fringilla teydea, is an endemic species of the Canary Islands. This species is formed by two subspecies: The Teneriffean blue chaffinch (F. t. teydea), and the endangered Gran Canarian blue chaffinch, (F. t. polatzeki). Here we report the isolation and characterization of nine tetranucleotide microsatellites (AAAG and AAAT) from the Gran Canarian subspecies, using an enrichment protocol. An average of 7.8 alleles per locus and an average observed heterozygosity of 0.773 were found (n = 28). The loci were tested for their ability to cross amplify in the Teneriffean subspecies and in the common chaffinch (Fringilla coelebs). These microsatellites will be used to manage a captive breeding programme for the endangered Gran Canarian subspecies.

Preferencias de hábitat, densidad y diversidad de las comunidades de aves en Tenerife (Islas Canarias)

Species–specific habitat preferences, density and species richness of bird communities in Teneriffe (Canary Islands) Bird distribution and abundance are described and analyzed in Teneriffe (Canary Islands). Inter–habitat differences in density, diversity and species richness are shown in table 1. Figure 2 shows the main determinants of bird species richness in Teneriffe, and tables 2 and 3 and figure 3 show the species–specific patterns of spatial variation abundance (more detailed for Anthus berthelotii, Fringilla coelebs canariensis, Fringilla teydea, Parus caeruleus teneriffae, Phylloscopus canariensis, Regulus teneriffae, Serinus canarius and Turdus merula cabrerae). Deeply transformed environments due to human impact (urban habitats, agricultural mosaics, banana plantations) have high bird densities and species richness, even higher than those measured in native, unmodified habitats such as laurel forests or mature pinewoods. Urban environments in Teneriffe are very permeable to native bird fauna, as they have been occupied by many widespread endemic species/subspecies. Many of the endemic, well defined species or subspecies of island birds have high population densities within native, untransformed habitats. Density compensation and niche expansion is not a common phenomenon in the avifauna of Teneriffe. Nevertheless, all species/subspecies broadening the inter–habitat or altitudinal distribution are endemic of the Canary Islands.

Biometrics, ageing, sexing and moult of the Blue Chaffinch Fringilla teydea teydea on Tenerife (Canary Islands)

The Blue Chaffinch Fringilla teydea is one of a few Palearctic species for which biometric data are lacking from the field; we address this issue here. Blue Chaffinches were caught by mist net, at ten sites on Tenerife (Canary Islands), and measured. Data on biometrics and moult using standard methods are presented, and observations on mass variation in relation to time of day and body size are reported for the first time. Wing length, bill length, bill depth & tail were greater in adults and first year birds than juveniles whilst tarsus and mass were the same. The species shows a clear sexual dimorphism in size except for bill length. The duration of primary moult was estimated to be 66 days for adults. For first year birds (in their second‐calendar year), the mean starting date of primary moult was 25 days earlier than adults and was completed after 109 days.

Mitochondrial DNA control region diversity in the endangered blue chaffinch, Fringilla teydea.

The blue chaffinch (Fringilla teydea) is found only on the two central Canary Islands of Gran Canaria and Tenerife, where it is restricted to pine forest habitat. It is reasonably abundant on the latter island but endangered on the former. Here, sequence variation was studied in a fragment spanning domains I and II of the mitochondrial DNA (mtDNA) control region. Phylogenetic analysis of all haplotypes with a F. coelebs outgroup indicated the two island populations were reciprocally monophyletic, supporting their individual conservation. Unlike in other species, most within-island haplotype diversity was due to mutations in the domain II region. Surprisingly, genetic diversity was greater in the smaller Gran Canarian population. We suggest that this is unlikely to be maintained under current population sizes although it may be mitigated by incorporating genetic information into the captive breeding programme.

Habitat Distribution of Canary Chaffinches Among Islands: Competitive Exclusion or Species-Specific Habitat Preferences?

The habitat distribution between islands of the Common Chaffinch (Fringilla coelebs L.), viewed in rela- tion to the presence of its potential competitor species, the Blue Chaffinch (Fringilla teydea Moquin-Tandon), has been studied for the Canary Islands (Tenerife and El Hierro). The Common Chaffinch was significantly denser in the pine woods of El Hierro than in Tenerife, while the Blue Chaffinch was only present in Tenerife. The vegetation structure was very different in the pine woods of the two islands. In the pine woods of El Hierro, the Common Chaffinch selected more grassy places, and foraged mainly in the foliage. The habitat selection pattern observed in Hierro was con- gruent with that obtained for the continental subspecies in the North of the Iberian Peninsula. An empirical model was thus developed to predict density variations of the Common Chaffinch in the continental pine woods of Northern Spain. This continental model (not subject to the influence of the potential competitive effect of the Blue Chaffinch) was then used to predict the abundance of the Common Chaffinch in the pine woods of El Hierro and Tenerife. The similarity between the densities predicted by the non-competitive continental model and those actually observed in the pine woods of El Hierro and Tenerife indicates that the presence of the Blue Chaffinch is not relevant in explaining the dif- ferences in Common Chaffinch density between islands. The habitat preferences of the Common Chaffinch quantita- tively explain density differences observed between El Hierro and Tenerife. These results show clearly the rele- vance of habitat structure in determining the patterns of presence and density of the Common Chaffinch between islands. Data obtained thus supports the species-specific habitat preference hypothesis, with the competitive exclu- sion hypothesis not being justified at least in ecological time.