Turtle Dove Streptopelia Turtur Research Articles

Age-specific differences in wing pointedness and wing length of European Turtle Doves Streptopelia turtur migrating through the eastern flyway

ABSTRACT Migration plays a significant part in shaping wing morphology in avian taxa. Differences in wing shape and size have been found to vary with regard to age and sex, as well as between different populations. Here, we examine age-related variation in the wing morphology of the European Turtle Dove Streptopelia turtur migrating through the eastern flyway. Wing morphology was examined by means of a size-constrained components analysis (SCCA) of standardised primary-feather lengths of 112 individuals killed by hunters. Our results showed that juvenile individuals had shorter and more pointed wings than adults, which is consistent with the pattern observed in individuals migrating through the western flyway. We conclude that in juveniles, the selection force of migration is perhaps stronger than selection of an anti-predator adaptation. Moreover, age-related variation in Turtle Dove wing morphology may influence juvenile survival, as well as migration timing, and both effects should be considered in future studies.

Trichomonas Infection in a Community of Free-Ranging Domestic and Wild Columbiformes and Bonelli's Eagle (Aquila fasciata).

Trichomonas gallinae is a pathogen of conservation relevance, whose main maintenance hosts are Columbiformes, but spillover to avian predators has been described. The goal of this study was to characterize the epidemiology of Trichomonas spp. in a community of free-ranging domestic and wild Columbiformes and an endangered predator, Bonelli's eagle Aquila fasciata. We surveyed 253 live-captured Rock doves, 16 nestling Bonelli's eagles and 41 hunted Columbiformes. Oro-esophageal swabs were incubated in culture media and Trichomonas spp. isolated from Bonelli's eagle (6.3%, CI95 1.1-28.3), Turtle dove Streptopelia turtur (56.3%, CI95 39.3–71.8), Wood pigeon Columba palumbus (83.3%, CI95 43.7–97.0) and Rock dove Columba livia (68.4%, CI95 62.4–73.8). Infected Rock doves showed significantly poorer body condition than uninfected ones (p = 0.022). From a subset of 32 isolates, 18S and ITS1/5.8S/ITS2 rRNA genes were sequenced and Maximum-Likelihood trees inferred. Four ribotypes of Trichomonas spp. were identified. In this study area Trichomonas spp. seem to persist in a multi-host system involving several species of Columbiformes. Conservation actions aimed at increasing the availability of trophic resources for Bonelli's eagles through Rock dove restocking should consider the risk of pathogen transmission and of introduction of alien strains.

Foraging Habitat Requirements of European Turtle Dove Streptopelia turtur in a Mediterranean Forest Landscape

Land use changes occurring in Europe in recent decades are generating important changes in the forest landscape characteristics and are having important effects on avian species richness and abundance. This is particularly important for some bird species of particular conservation concern that require heterogenous landscapes where breeding habitats are proximal to foraging habitats. Among these birds, the European Turtle Dove Streptopelia turtur is particularly important because of its marked population decline. In southern Europe, forest landscapes have been considered important breeding areas for Turtle Doves. We assessed the influence of the foraging area characteristics — distance to cereal crops and wild seed species abundance — and water availability on Turtle Dove breeding habitat suitability in a Mediterranean forest landscape in southern Spain. Forty-six point locations were surveyed during the spring of 2014 and 2015 on two nearby farms of a forest protected area. The average local abundance of Turtle Doves found at each point location was 1.25 ± 1.31 males, and it was significantly higher at the point locations closest to cereal crops, as well as at nesting sites where the wild seed species included in its local diet were abundant, especially Echium plantagineum. Distance to water in the studied range (average distance 475 m) did not show a significant effect on Turtle Dove local abundance, although the high availability of water in the study area could have a positive influence on the overall Turtle Dove breeding habitat suitability. To benefit Turtle Dove breeding habitat suitability, cultivated areas with cereals/legumes near those forest areas where Turtle Doves reproduce should be promoted. Likewise, the promotion of those herbaceous species that are locally important in the Turtle Dove diet, available, for example, through specific grazing management, should be taken into account when nesting habitat restoration is designed in forest areas, regardless of whether the distances to food resources are long.

Bird species’ richness, relative abundance and conservation status in protected and unprotected areas of the Hadejia-Nguru Wetlands, north-east Nigeria

The role of protected areas is for the long-term conservation of biodiversity. This study investigated the effectiveness of the Hadejia-Nguru Ramsar Wetlands Protected Areas in maintaining bird community. We assessed and compared species’ richness, relative abundance and conservation status of birds between Protected Areas (PAs) and Unprotected Areas (UPAs) of the wetland. The study was conducted from October to December, 2015. Point-count method was employed during the study. Forty-eight points of 100 m radius and 400 m intervals were surveyed in PAs and 51 points in the UPAs. A total of 42, 255 individual birds of 148 species’ belonging to 23 orders and 50 families were recorded. Uprotected Areas had 133 species and PAs 121 species (p = 0.4514), however, PAs had higher birds abundance than unprotected areas. The two areas shared a greater percentage of species composition by 85%. Two globally threatened species were also recorded, the European Turtle Dove Streptopelia turtur (Vulnerable) and Pallid Harrier Circus macrourus (Near Threatened). White-faced Whistling Duck Dendrocygna viduata, and Garganey Spatula querquedula were the dominant species in both areas. Results further revealed that PAs had slightly higher bird population with stable trend than UPAs, in contrast, though those with increasing population were more in UPAs. Overall, the population trend of birds in both habitats was found to be stable. Majority of resident species’ population trend were found to be on the increase, or stable, while intra- African and Palearctic migrants were found to be declining. This study highlights that not only PAs of the HNWs are important for bird conservation, but UPAs, too, are of great significance for the long-term conservation of the wetland bird community. Legal protection of certain wetland areas especially in the UPAs may help preserve larger bird species.Keywords: Bird conservation; Hadejia-Nguru Wetlands; protected and unprotected areas; threats.

Species distribution models of European Turtle Doves in Germany are more reliable with presence only rather than presence absence data

Species distribution models (SDMs) can help to describe potential occurrence areas and habitat requirements of a species. These data represent key information in ecology and conservation, particularly for rare or endangered species. Presence absence (PA) and presence only (PO) records of European Turtle Doves Streptopelia turtur in Germany were used to run SDMs, whilst climate and land coverage variables provided environmental information. GLM (Generalised Linear model), GBM (Generalised Boosted model), CTA (Classification Tree analysis), SRE (Surface Range Envelope) and RF (Random Forests) algorithms were run with both datasets. Best model quality was obtained with PO in the RF algorithm (AUC 0.83). PA and PO probability maps differed substantially, but both excluded mountainous regions as potential occurrence areas. However, PO probability maps were more discriminatory and highlighted a possible distribution of Turtle Doves near Saarbrucken, west of Dusseldorf, in the Black Forest lowlands and Lusatia. Mainly, the climate variables ‘minimum temperature in January’ and ‘precipitation of the warmest quarter’ shaped these results, but variables like soil type or agricultural management strategy could improve future SDMs to specify local habitat requirements and develop habitat management strategies. Eventually, the study demonstrated the utility of PO data in SDMs, particularly for scarce species.

High prevalence of Trichomonas gallinae in wild columbids across western and southern Europe

BackgroundAvian trichomonosis is known as a widespread disease in columbids and passerines, and recent findings have highlighted the pathogenic character of some lineages found in wild birds. Trichomonosis can affect wild bird populations including endangered species, as has been shown for Mauritian pink pigeons Nesoenas mayeri in Mauritius and suggested for European turtle doves Streptopelia turtur in the UK. However, the disease trichomonosis is caused only by pathogenic lineages of the parasite Trichomonas gallinae. Therefore, understanding the prevalence and distribution of both potentially pathogenic and non-pathogenic T. gallinae lineages in turtle doves and other columbids across Europe is relevant to estimate the potential impact of the disease on a continental scale.ResultsWe examined 281 samples from four wild columbid species for Trichomonas infection and determined the genetic lineages. The overall prevalence was 74%. There were significant differences between the species (P = 0.007). The highest prevalence was found in stock doves Columba oenas (86%, n = 79) followed by wood pigeons Columba palumbus (70%, n = 61) and turtle doves (67%, n = 65), while three of five collared doves Streptopelia decaocto (60%) were infected. We found seven different lineages, including four lineages present in columbids in the UK, one lineage already described from Spain and three new lineages, one of those found in a single turtle dove migrating through Italy and another one found in a breeding stock dove. Stock doves from Germany and collared doves from Malta were infected with a potentially pathogenic lineage (lineage A/B), which is known to cause lesions and mortality in columbids, raptors and finches.ConclusionsGenerally, turtle doves showed high prevalence of Trichomonas infection. Furthermore, the potentially pathogenic lineage A/B (or genotype B according to previous literature) was found in a recovering stock dove population. Both findings are worrying for these columbid species due to the occasional epidemic character of trichomonosis, which can have severe negative effects on populations.

European Turtle Dove Streptopelia turtur diet composition in Southern Spain: the role of wild seeds in Mediterranean forest areas

ABSTRACTCapsule: The diet of European Turtle Doves Streptopelia turtur in Mediterranean forest contained a large volume of wild plant seed but from a small number of key species.Aims: To determine which seed species are consumed by Turtle Doves in Mediterranean forest areas.Methods: Digestive tract contents were identified and evaluated for 222 Turtle Doves shot by hunters during three consecutive years.Results: Thirty seed species were identified in the diet, but only a few species represented most of the volume and frequency. Wild plant seeds appeared in 65.8% of digestive tracts and showed significant variation between years. Although the main wild seed species consumed each year varied annually, certain species were found in the diet every year in high volume and frequency. Adults showed a more diverse and numerous consumption of wild seeds than did juveniles. Plastic granules were also found in 3.8% of individuals.Conclusion: A greater number of wild seed species was found in the diet in contrast to previous studies performed in farmland. Echium plantagineum and Amaranthus deflexus could be important seed sources for Turtle Doves in Mediterranean forest. Additionally, the herbaceous species found in the diet whose seeds ripen earlier in the season might play an important role in Turtle Dove reproductive performance, since they are frequently the only available food in the first half of the breeding season.

Analysis of Ring Recoveries of European Turtle DovesStreptopelia turtur— Flyways, Migration Timing and Origin Areas of Hunted Birds

Abstract. Knowledge about flyways, breeding and overwintering sites is important for conservation efforts, but little is known about migration patterns and population connectivity of declining European Turtle Doves Streptopelia turtur. EURING ring-recovery data were used to estimate directions and proportional usage of flyways. The timing of migration was compared along these routes and breeding origins of shot individuals were determined. Ring recoveries of Czech, Hungarian, British, German and French birds suggested three main flyways with westerly, central and easterly directions. The proportional usage was estimated by multinomial mark-recovery models. Major parts of French (62%), German (92%) and British (94%) Turtle Doves followed a western flyway. Czech birds used the central route (56%) and 55% of Hungarian birds followed the eastern flyway. Thus, a migratory divide between the Czech Republic and Germany could be suggested. The timing of migration showed a similar latitudinal pattern of migration ...

Turtle Dove Streptopelia turtur migration routes and wintering areas revealed using satellite telemetry

ABSTRACTSatellite telemetry of two European Turtle Doves Streptopelia turtur confirmed the broad patterns suggested by earlier work using geologgers but also revealed that they migrated by night and used four distinct stopover and two wintering sites. Winter habitat used by one bird covered less than 100 km2 per site, much smaller than previously assumed.

Effects of orchard type and breeding period on Turtle Dove nest density in irrigated agroecosystems

Capsule The density of nests of the Turtle Dove Streptopelia turtur in Moroccan irrigated agroecosystems was 68% higher in orange orchards than in olive orchards, and 42% higher in the early breeding period compared to the late period. Agricultural practices and hunting activity are the main factors affecting this vulnerable species.

Effect of supplementary food on age ratios of European turtle doves (Streptopelia turtur L.)

Many farmland birds have difficulties finding sufficient food in intensely managed agricultural ecosystems, and in more extensively worked landscapes they are often attracted to human–induced dietary sources. European turtle doves Streptopelia turtur feed on seeds collected on the ground, and are readily attracted to supplementary provided grain at feeding stations. Supplementary feeding is a common management practice on hunting estates around the world. This study was conducted in 40 hunting estates located in central west Spain: 20 sites where supplementary food was provided to attract turtle doves and 20 control sites without feeding stations. At sites with supplemental feeding, the field age ratio was 20% higher and the hunted age ratio was 33% higher than at control sites, indicating a positive effect of the food supplementation of the breeding success around supplemented sites. Both the amount of food provided per day and the amount of time where supplemental food was given (20–120 days) were positively correlated with the field age ratio and, less strongly, with the hunted age ratio. These data suggest that providing extra food can increase the breeding success of this species when the amount provided is sufficiently large and when supplementary food is provided early in the breeding season. However, hunting pressure was also higher at supplemented sites. Future studies should therefore closely monitor the positive and negative effects in order to ascertain which management practices will ensure the viability of these important European turtle dove populations.

Testing bespoke management of foraging habitat for European turtle doves Streptopelia turtur

Agri-environment schemes (AES) are increasingly being employed to mitigate biodiversity loss in agricultural environments. The European Turtle Dove Streptopelia turtur is an obligate granivorous bird in rapid decline within both the UK (−96% since 1970) and across continental Europe (−77% since 1980), despite widespread uptake of AES. Here, we assess the efficacy of a potentially new, sown agri-environment option designed to provide abundant, accessible seed for S. turtur during the breeding season. During summer 2011 we compared vegetation structure and seed provision on trial plots to control habitat types (existing agri-environment options thought to potentially provide S. turtur foraging habitat) to assess whether trial plots performed better for foraging S. turtur than control habitats. In September 2011 all trial plots were topped (cut) and half of a subset of trial plots were then scarified (60% of soil surface disturbed). Vegetation structure on topped, and topped and scarified trial plots was measured during summer 2012 to determine which management regime was most effective in maintaining suitable sward structure and seed provision into the second year. No control habitat type produced as much seed important in S. turtur diet as trial plots at any point during year one. Trial plots provided accessible vegetation structure early in the season with no difference in vegetation metrics between trial plots and previously published data on S. turtur foraging locations. However, to allow later access, management is required during mid-June to open up the sward through localized topping or scarification. Vegetation structure during year two was generally too dense to attract foraging S. turtur. However, scarifying trial plots during the September following sowing encouraged self-seeding of Fumaria. officinalis (a plant species historically forming a significant proportion of S. turtur diet during the breeding season) into the second year, with this species present in 16% of scarified trial plots compared to only 4% of topped trial plots during year two. Thus, autumn scarification, possibly followed by topping or scarification of part of the trial plots in June, is necessary for trial plots to provide more seed and access for S. turtur than existing agri-environment options during year two. We recommend modifications to our original seed mix in order to reduce vegetation density and improve vegetation structure. The study provides an example of the need to strike the right balance between food abundance and accessibility, through vegetation structure, when designing agri-environment scheme management options that provide food for birds.

Are nest-detection probability methods relevant for estimating turtle dove breeding populations? a case study in Moroccan agroecosystems

Knowing the population size of game is a basic prerequisite to determining adequate hunting management and conservation strategies and setting up appropriate hunting quotas. This study compared three methods complete count, capture–recapture and N-mixture modelling to estimate a turtle dove Streptopelia turtur breeding population using nest counts. We randomly sampled 143 fruit farms (60 orange orchards and 83 olive orchards) situated in an irrigated area in Morocco at the peak of breeding activity. We calculated the probability of detecting active turtle dove nests using information from two observers who independently searched the same sample plots. We found that (a) the capture–recapture method provided more precise results of nest abundance than N-mixture modelling, and that (b) the probability of nest detection was noticeably different between the two study orchards—higher in the orange orchards than in the olive orchards. Although these two methods are easy to implement and cost-effective for estimating population abundance on a large spatial scale, our results demonstrate that the resulting estimates are prone to bias depending on the tree height of the plantations. Of the three methods for estimating turtle dove abundance, complete counts were preferable for assessing population size. Using the complete counts, the density of turtle dove nests was found to be 2.96 nests/ha in the orange orchards and 0.93 nests/ha in the olive orchards. A density extrapolation to the entire surface area of the Tadla Region indicated a minimum breeding population size of 58,969 pairs (95 % confidence interval: 48,550–69,353).

Ringing studies of the turtle dove Streptopelia turtur (Aves: Columbidae during passage through Antikythera Island, southwestern Greece

The aim of this study is to describe the phenology of migration and biometrics of the turtle dove Streptopelia turtur in Greece, based on ringing studies on Antikythera Island. Spring passage takes place between early April and late May and autumn passage between early and late September. There is no significant difference in either wing length or tarsus length between adults and juveniles. Males have significantly greater wing length. There is no significant difference in tarsus length between the two sexes.

Breeding Habitat Use and Conservation Status of the Turtle DoveStreptopelia turturin Northern Spain

SUMMARY. We investigated the abundance and breeding habitat use of the turtle dove Streptopelia turtur in the Basque Country (northern Spain). Censuses employed 500 m transects, distributed across 100 km2 grid cells where the species was previously known to occur. Turtle doves were only detected in two out of four biogeographic sectors sampled. The species was found in forested habitats, riparian forests and evergreen oak patches in particular, but its abundance decreased as tree cover increased. The abundance in farmland was lower, probably as a consequence of the scarcity of adequate nest sites. The range contraction described for this population stresses its unfavourable conservation status and the need to implement action, especially in relation to its breeding habitats.

Which features of UK farmland are important in retaining territories of the rapidly declining Turtle Dove Streptopelia turtur?

Capsule Turtle Doves continue to show a strong population decline; territories were more likely to be retained in areas with more nesting habitat, and more suitable foraging habitat. Aim To determine which features of farmland in England are important for retaining Turtle Dove territories Methods Fifty-eight grid squares with recent records of territorial Turtle Doves were resurveyed, and squares retaining Turtle Dove territories compared with those from which Turtle Doves had been lost. Results Turtle Dove territories were detected in 48% of squares resurveyed. When correcting for the 70% detection rate of the survey methodology, territories were present in 66% of squares surveyed suggesting a 34% decline over a 2-year period. Established scrub and hedgerows > 4 m tall positively influenced Turtle Dove presence and abundance, as did standing water. Bare ground and fallow had positive effects on Turtle Dove abundance whereas grazed land negatively impacted abundance. Conclusion The positive effects of area of established scrub and volume of large hedgerows are likely to represent a declining density of birds selecting the best quality nest sites. We suggest instead that foraging habitat may be limiting distribution.

Do age and type of plantings affect turtle dove Streptopelia turtur nest placement in olive agro-ecosystems?

Seventy active turtle dove nests were found in the Tadla irrigated olive agro-ecosystem, 39 in olive orchards and 31 in olive hedgerows. A two-way multivariate analysis of variance (MANOVA) was performed to determine the combined effects of olive age categories (class A < 10 years, class B 10–20 years and class C 21–30 years) and type of plantings (orchards and hedgerows) on nest placement within-tree. Results indicated that turtle doves' nests are placed higher up gradually as the trees are older. Nonetheless, the nest's relative vertical position in the canopy does not change from one age to another. Nest placement in the canopy was higher in hedgerows than in orchards. This game species exhibits adaptive behavioural plasticity in nest placement and appears well-adapted to olive grove conditions in this region. This high adaptability is beneficial to maintaining the species in these highly frequented man-made environments.

Longer term trends in arrival timing of long distance migrants: the influence of abundance and population change

The first arrival dates for summer migrants in Cheshire and Wirral indicate a longer term trend towards earlier arrival since the mid 1970s, consistent with the findings of previous studies based on first arrival data from UK area bird reports. The aim of this study was to investigate the influence of abundance and population change on the apparent advancement of arrival dates. Stronger apparent advancement in arrival was observed for species which have increased in numbers in the county over recent years, for example Hobby Falco subbuteo. Less common and declining species, such as Turtle Dove Streptopelia turtur, Yellow Wagtail Motacilla flava, Wood Warbler Phylloscopus sibilatrix, Willow Warbler P. trochilus and Spotted Flycatcher Muscicapa striata, showed some of the lowest rates of advancement. These observations can be interpreted in terms of the dependence of the first arrival date on the probability of detection of individuals, which is dependent on the level of abundance of a species as a whole, and hence on changes in abundance. Theoretical considerations indicate that changes in abundance are likely to have more of an impact on the apparent advancement rate of arrival for less abundant species than for more abundant ones. Such factors may in part explain the regional differences that have been observed in apparent advancement rates for some species.

Are Moroccan fruit orchards suitable breeding habitats for Turtle Doves Streptopelia turtur?

Capsule Although subject to human disturbance Turtle Doves do nest successfully in these olive and orange orchards. Aim To investigate the breeding ecology of Turtle Doves in a man‐made agricultural habitat in central Morocco. Methods Turtle Dove nests were monitored in orange and olive orchards over three years (2006, 2007 and 2008). Nest abundance, nest location, egg‐laying chronology, clutch size, nest survival rates and breeding success were determined and compared between orchard types. Results The Moroccan population of Turtle Doves start breeding earlier than European populations. Clutch size, nest survival rates and breeding success were similar in orange and olive orchards. Nest location differed between orange and olive trees. Nest densities were 16 nests/ha in olive orchards and 45 nests/ha in orange orchards. Nest success rate averaged 48%. Daily nest survival rates did not vary according to orchard types, year and date. In the two orchards, no nest position variables were significant predictors of nesting success. Conclusion Although highly frequented by people, fruit orchards seem to be suitable breeding habitats for Turtle Doves in this region.

Adjustment of incubation according to the threat posed: a further signal of enemy recognition in the Blackcap Sylvia atricapilla?

Nest predation and brood parasitism are costly for nest owners, and natural selection should therefore favour the evolution of parental counterdefences. We addressed the question of whether Blackcaps Sylvia atricapilla change their incubation behaviour in response to various nest intruders and whether this adjustment matches the intensity of mobbing exhibited towards these intruders. Near focal nests, we successively exposed a dummy of a brood parasite, nest predator and an innocuous species. After the parents had responded, we removed the dummy and filmed their incubation. The most aggressive response towards the Common Cuckoo Cuculus canorus and high nest attendance after its disappearance indicated recognition of the brood parasite. Low-intensity response to the Jay Garrulus glandarius, together with reduced subsequent parental care, suggested that Blackcaps perceived it either as less deleterious at the egg stage than the Cuckoo or as a danger to themselves. Almost no aggression towards the Turtle Dove Streptopelia turtur, along with the resumption of incubation after its removal, implied that Blackcaps recognised it as harmless. In addition, we found that the level of aggression positively correlated with nest attendance, suggesting a link between the intensity of mobbing and subsequent parental care. Altogether, our results demonstrate that the issue of enemy recognition may be viewed as a complex of both aggressive and post-presentation behaviours.