Evidence from DNA nucleotide sequences and ISSR profiles indicates paraphyly in subspecies of the Southern Grey Shrike (Lanius meridionalis)

We obtained DNA sequence data from mitochondrial (cytochrome b) and nuclear genes (myoglobin and ornithine decarboxylase) to reconstruct the phylogenetic relationships among eight species of shrikes (Lanius). Phylogenetic analyses based on maximum parsimony, maximum likelihood and Bayesian inference all converged into a congruent topology and defined several well-supported clades. Our multi-gene approach based on nucleotide sequences from fast-evolving and conserved genes strongly supported the paraphyly of Southern Grey Shrikes (Lanius meridionalis). The Canary Islands subspecies (L. m. koenigi) differed significantly from its European counterpart (L. m. meridionalis). Furthermore, the genetic distinctiveness of L. m. koenigi was confirmed by ISSR genomic fingerprinting. By contrast, we did not find evidence to distinguish the Canarian Southern Grey Shrike from L. m. algeriensis on the African mainland (Tunisia), and therefore these two taxa may be considered as synonymous. Together, they correspond to a separate species. The origin of the taxa investigated in this study might have originated about 6 Mya at the Miocene/Pliocene boundary when a remarkable worldwide faunal turnover and global vegetation change occurred. The Lanius genus represents a complex and taxonomically challenging group that requires additional research.     

Der Handflügelindex südwestpalaearktischer Raubwürger (Lanius excubitor) — Kritik eines Klischees

Zusammenfassung Der klassische Fall von Zuganpassung im Flügelbau der europäischen Würger (Lanius minor, L. excubitor) ist Anlaß zu einer kritischen Betrachtung. Diese erfolgt durch Vergleich der Proportionsunterschiede südwestpalaearktischerL. excubitor (und asiatischerL. excubitor/L. sphenocercus), die trotz erheblicher Divergenzen keine Zuganpassungen sein können. Sie sind allometrisch (L. e. koenigi) oder im Zuge evolutionärer Trends durch effektive Umkonstruktion bedingt. Der Fall zeigt, daß die Zusammenführung vergleichender Untersuchungen in Systematik, Zoogeographie, Morphologie und Ökologie verstärkt zu werden verdient.

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The wing tip index of southwest Palaearctic Great Grey Shrikes (Lanius excubitor) — a hackneyed phrase re-analyzed

Summary The classical case of migrational adaptation in wing construction of European Grey Shrikes (Lanius minor, L. excubitor) is re-investigated critically. The study is based on the comparison of proportional differences of SW PalaearcticL. excubitor and AsianL. excubitor/L. sphenocercus wings. Despite considerable differences these cannot considered as migrational adaptations. They are allometric (L. e. koenigi) or they are caused by constructive differentiation within evolutionary trends. As shown in this example, comparative investigations in systematics, zoo-geography, morphology, and ecology need to be enhanced and the results to be viewed multidisciplinary.

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Dem Andenken an Dr. H. E. Wolters gewidmet     

Temporal changes and sexual differences of impaling behavior in Southern Grey Shrike (Lanius meridionalis)

The Southern Grey Shrike (Lanius meridionalis) is a common resident along the rift valley. During 2007-2008 we studied the impaling behavior of Southern Grey Shrikes at the Shezaf nature reserve by food supplementation. Our findings indicate seasonal shifts in impaling behavior. During the winter, there was no difference between the sexes and shrikes impaled house mice (Mus musculus) close to their territorial boundaries with neighboring conspecifics. All impaled mice disappeared from the tree within a few hours of impalement. During the mating season, males impaled the whole prey and let females eat it, and prey was impaled by both sexes only in order to dismember and feed the nestlings. Shrikes impaled and cached meal worms only after they were satiated. The number of meal worms taken to be hoarded increased during the non-breeding season, but during the breeding season male shrikes preferred to feed the females. During the entire research period we did not find any specific cache sites or trees and no prey remained impaled for extended periods of time. In conclusion, impaling prey changed temporally and between sexes: from being a signal for conspecifics to pair bonding.     

Habitat preferences of Red-backed Shrikes Lanius collurio and Barred Warblers Sylvia nisoria breeding sympatrically in a wetland/farmland mosaic

Capsule: The Red-backed Shrike Lanius collurio and the Barred Warbler Sylvia nisoria had similar habitat preferences and their territories often overlapped. However, we found that Red-backed Shrikes were more flexible in habitat choice whilst Barred Warblers had more specific requirements.

Aim: We aimed to analyse and compare distribution and habitat preferences of Red-backed Shrikes and Barred Warblers breeding sympatrically in semi-natural landscape in a wetland/farmland mosaic.

Methods: We examined habitat availability and use by the two species within their breeding territories to identify differences in habitat selection.

Results: Territories of both species were similar in habitat composition and used levees, bushes, fallow areas and single trees. However, the spatial characteristics of the territories differed between species. Red-backed Shrikes used a wider range of sizes and shapes of habitat patches, whilst Barred Warblers preferred a more complex landscape structure and a higher diversity of habitat types. We also found that areas of 71% of Barred Warbler and 34% of Red-backed Shrike territories overlapped.

Conclusion: Whilst both species showed similar habitat choices, they appeared to differ significantly in terms of landscape structure: Red-backed Shrikes were more flexible and less selective than Barred Warblers in their habitat choice.     

Spring migratory routes of eight trans-Saharan passerines through the central and western Mediterranean; results from a network of insular and coastal ringing sites

Detailed information on spring migration routes of songbirds across the Mediterranean is still scanty. Results are presented here from a study on the occurrence of eight Palaearctic-African migrants across the western and central Mediterranean based on ringing data collected during the Progetto Piccole Isole, a co-ordinated project based on standardized mist netting at 21 islands and coastal stations. The species were Melodious Warbler Hippolais polyglotta , Icterine Warbler Hippolais icterina, Bonelli's Warbler Phylloscopus bonelli , Wood Warbler Phylloscopus sibilatrix , Pied Flycatcher Ficedula hypoleuca , Collared Flycatcher Ficedula albicollis , Red-backed Shrike Lanius collurio and Woodchat Shrike Lanius senator . Their capture frequencies were expressed as the frequency of each species relative to the total number of migrants ringed at each station in order to correct for differences in capture effort between stations. For most species, the detailed, quantitative results confirmed the scanty information available so far, whereas in the case of Melodious Warbler and Bonelli's Warbler, evidence of undescribed and unexpected migration routes was found. These results suggest that standardized mist netting provides an important method for studying the migratory routes of small birds, in particular for those species which are not frequently ringed in their breeding and wintering grounds.     

Between land abandonment and agricultural intensification: habitat preferences of Red-backed Shrikes Lanius collurio in low-intensity farming conditions

Capsule The conservation of Red-backed Shrikes on farmland habitats depends on extensive farming conditions.

Aims To evaluate breeding density and habitat preferences of the declining Red-backed Shrike and relate its occurrence to an environmental gradient ranging from land abandonment to intensive farming.

Methods The study was carried out in the Apennines (northern Italy), at nine 21-ha study plots. We identified factors affecting breeding density and habitat preferences at two spatial scales (landscape and territory) and analysed the variation in territory density according to the relative farming intensity in a low-intensity agricultural landscape.

Results The presence of shrubs and cultivated/grazed land positively influenced the number of Red-backed Shrike territories per plot, while the species' settlement within plots was related to higher values of shrub cover and the presence of hedges. Shrike occurrence was associated with land-use categories intermediate between land abandonment and intensive agriculture.

Conclusions This study provides a first detailed assessment of Red-backed Shrike habitat requirements in southern Europe. Favoured habitats were pasture/cultivation mosaics flanked by or interspersed with shrubs/hedges (15–20% of the surface of the 1-ha medium-sized territory). Thus, the conservation of Red-backed Shrikes in low-intensity southern European farmland appears to reflect a trade-off between agricultural intensification and long-term land abandonment.     

Using FTA® cards to store avian blood samples for genetic studies. Their application in sex determination

FTA® cards were used for long‐term storage of avian blood samples. Blood DNA was extracted by a simple method and used in PCR for sex identification of adult and nestling Great Grey Shrikes Lanius excubitor.     

Storing prey in larders affects nestling haematological condition in the Red-backed Shrike (Lanius collurio)

Many animals, including shrikes (Laniidae), are known to store food. This behaviour ensures food availability during inclement weather, for rearing nestlings or signalling territory quality. Unlike most other shrike species, which accumulate food before breeding, Red-backed Shrikes Lanius collurio store food in larders, mainly during the nestling and fledgling periods. If this is an adaptive behaviour, variation in this behaviour should affect either or both the number and condition of nestlings, which may benefit from such larders. We assessed the haematological condition of Red-backed Shrike nestlings in east-central Poland in 2021 using a suite of blood parameters relating to sites where shrikes did or did not store food. Haemoglobin concentrations were positively correlated with larders, being significantly higher in nestlings of pairs that stored prey compared with those whose parents did not do so. White blood cell counts were lower in nestlings whose parents kept larders. Red blood cell counts and glucose concentrations in nestlings were not related to whether parents had larders. Food storage probably ensures a more constant access to food, which results in a superior haematological condition in nestlings.     

A new material for old solutions—the case of plastic string used in Great Grey Shrike nests

Innovative behaviours are defined as new behaviour patterns derived by the modification of pre-existing ones. To date, studies of animal innovation have focussed mainly on foraging activity. In this paper, we focussed on the innovative use of a new material—man-made plastic (polypropylene) string—in nest construction by a solitary nesting, territorial species, the Great Grey Shrike Lanius excubitor. An analysis of field data collected during the years 1999–2006 during intensive shrike research in Poland, as well as of nest record cards since 1964, suggests that plastic string has been a very popular nest material since the 1980s. Recently, plastic string was used significantly more often by shrikes living in intensive farmland habitats than by those in more natural meadows. We discuss the possible benefits of the use of plastic string, such as strengthening the nest structure and therefore helping to protect eggs and nestlings from inclement weather conditions, such as strong winds. On the other hand, the use of plastic string has a real cost for breeding Great Grey Shrikes because both adult birds and nestlings may get tangled in it.     

Is the nesting association between the Orphean Warbler (Sylvia hortensis) and the Woodchat Shrike (Lanius senator) an anti-predator oriented mutualism?

As already pointed out in the Red-backed ShrikeLanius collurio (and Isabelline ShrikeL. isabellinus) and the Barred WarblerSylvia nisoria, the Woodchat Shrike and the Orphean Warbler form a species pair engaged in a breeding association. Nest recordings of both species in the same bushes along with behavioural evidence in southern France suggests that this association goes far beyond a simple commensalism (for the sole benefit of the warbler) but might be considered as an anti-predator oriented mutualism whose precise extent evidently needs further observations.

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Zusammenfassung Rotkopfwürger und Orpheusgrasmücken gemeinsam im selben Nestträger nistend und weitere Verhaltensbeobachtungen an diesen beiden Arten in Süd-Frankreich lassen, wie schon zwischen Neuntöter (und weiter östlich Isabellwürger) und Sperbergrasmücke erwiesen, auf eine vermutliche Nestfeind-orientierte Assoziation schließen, woraus beide Arten Nutzen ziehen. Weitere Beobachtungen müssen Eigenschaften und Grenzen dieser Assoziation zeigen.

     

Sexing adult Northern Shrikes using DNA, morphometrics, and plumage

ABSTRACT.   Northern Shrikes ( Lanius excubitor ) are predatory songbirds found primarily in taiga regions throughout their Holarctic breeding range. The species is poorly known, especially in North America, and is generally thought to be sexually monomorphic. From 2004 to 2007, we captured 50 adults in northern Wisconsin during the nonbreeding season (December–March) and determined sex using DNA extracted from feather samples. Males had significantly longer wings, longer tails, and less black in the outer rectrix than females, but body mass did not differ between the sexes. A discriminant function equation using tail length and extent of black on the outer rectrix correctly assigned the sex of 97.4% of captured adults. Plumage dimorphism was also evident, with males having paler gray heads and backs without brown tones, whiter underparts with lighter barring, and a more distinct and horizontal border at the base of the sixth primary feather. The ability to accurately determine sex will provide opportunities to examine possible inter- and intrasexual differences in the behavior and ecology of adult Northern Shrikes.     

Hatching order and sex ratio in Southern Grey Shrike Lanius meridionalis in relation to clutch size

Despite major advances in sex ratio theory, how offspring sex should vary with hatching order remains unclear. We examine nestling sex ratio in the Southern Grey Shrike Lanius meridionalis according to hatching order and clutch size. Southern Grey Shrike nestlings present a different sex ratio with body‐mass rank order depending on clutch size. When the clutch size was five eggs (with a very low risk of brood reduction; 13%) the less costly sex (male) was found at the end of the body mass hierarchy. However, when clutch size was six eggs (with a high risk of brood reduction; 42%) the larger sex (female) was found at intermediate positions in the hatching order, possibly to decrease competitive asymmetries.     

Seasonal change in Red-backed Shrike Lanius collurio territory quality - the role of nest predation

This paper examines the relationships between territory preference, reproductive performance and nest predation in a Red-backed Shrike Lanius collurio population breeding in rapidly changing farmland. Territory preference was measured by (a) the order of laying dates in territories within years and (b) territory occupation frequency over a five-year period. Seven environmental variables were tested but only the density of Sloe (Blackthorn) Prunus spinosa in territories was correlated positively with territory occupation frequency. Within years, Red-backed Shrikes started to breed earlier in territories with more Sloe, but reproductive performance was not related consistently to territory differences. A high proportion of Sloe-rich territories was vacant each year. Thus, the observed negative association between settlement order and amount of Sloe may reflect a seasonal change in habitat preference. Early breeders prefer Sloe-rich territories whereas late birds prefer Sloe-poor territories. Supporting evidence is that the proportion of occupied territories that was Sloe-rich was higher for early than for average or late first breeding attempts. Moreover, in contrast to early in the season, the probability of a replacement clutch following nest failure was not associated with the amount of Sloe, but increased with increasing densities of Juniper Juniperus communis. Late in the nesting season, pairs breeding in Sloe-rich territories suffered higher nest predation than those breeding in Sloe-poor territories. In early nesting attempts, however, the relationship was reversed. Nest predation is probably an important selective agent on habitat selection since it was the principal factor explaining variation in the numbers of fledglings produced among territories. Thus, the Red-backed Shrike may shift territorial preferences adaptively as the season progresses to match within-season changes in predation pressure in different types of territories.     

Foraging behaviour and diet in two sympatric shrike species during autumn migration across the Arabian Peninsula

In situations of restricted food supply, the trophic niches of closely-related species of animals should be separate. For sit-and-wait hunters, such as shrikes, this is associated with competition for food and hunting sites. In the present study, the foraging behaviour of two shrike species – Red-tailed Shrike Lanius phoenicuroides and Red-backed Shrike Lanius collurio – was studied in a desert habitat in Oman. The fieldwork was carried out in September 2019, during the peak migration of these birds. Their behaviour was recorded in detail during 30-minute observation bouts. A General Linear Mixed Model with logit link function and binomial error variance was used to compare their behaviour. The type of perch and its height did not differ between them, but there were significant differences in their use of look-out posts only in the mean duration of a single perching event, which was more than twice as long in Red-backed Shrike. No differences in prey size were found between the species and hunting success (the ratio of successful attacks to all attacks) was similar in both (RtS-RbS: 46 vs. 61%). Dietary diversity was twice as great in Red-tailed Shrike as in Red-backed Shrike, but in general, their diets did not differ very much. Dietary overlap between the species at this level of prey identification was 92%. This absence of differences in some aspects of behaviour and diet may be due to the similarity of the two species, above all their same body size, and even the possibility of hybridization. If the species compared are so similar due to body size, behaviour and evolutionary relationship their food niches may overlap.     

Patchy versus linear non-cropped habitats in farmland: which is better for nesting success of the Red-backed Shrike Lanius collurio?

Capsule: The survival rate of Red-backed Shrike Lanius collurio nests in western Poland was higher when they nested in bushes aggregated in patches, rather than linear formations.     

Trophic ecology of the Southern Grey Shrike (Lanius meridionalis) in insular environments: the influence of altitude and seasonality

The seasonal diet and prey selection of the Southern Grey Shrike (Lanius meridionalis) was studied in two different insular habitats: shrub environments of the Canary Islands in coastal and high mountain zones. We measured, in each season, food availability and prey size in order to determine prey size selection of shrikes along an altitudinal gradient. Moreover, we compared the diet patterns observed with those documented on the continent, to determine if Southern Grey Shrikes in the islands’ high mountain zone (which has a continental climate) showed seasonal diet variation similar to those in northern continental areas. We analysed a total of 1,139 shrike pellets collected in 1 year and identified 10,179 prey items. Numerically arthropods (91%), and in terms of biomass lizards (70%) were the main prey consumed by the shrikes. The proportions of the main prey items differed significantly between seasons and habitats. Diet in the coastal areas was less variable than in the high mountain zone. The greater seasonal climatic variation in the high mountain zone was associated with diet patterns similar to those found in some northern continental areas, such as the Iberian Peninsula and southern France. Finally, shrikes selected the largest prey in the high mountain habitat. This suggests that foraging behaviour in this species is related to climatic conditions, as the biggest and most profitable prey were consumed in the most harsh habitats.     

Rapid moult among palaearctic passerines in West Africa- an adaptation to the oncoming dry season?

Moult of some palaearctic migrant passerines was studied at a wintering site in northern Ghana, West Africa. We present data on moult pattern and estimated moult duration for a sample of species. Savi's Warbler Locustella luscinioides , Woodchat Shrike Lanius senator and probably Grasshopper Warbler Locustella naevia deviated from the ordinary descendent moult sequence. Different measures of moult speed (moult speed of retrapped individuals, growth of individual feathers, wing raggedness and first date of completion of moult) showed unexpectedly rapid moult among individuals of several species, notably the Great Reed Warbler Acrocephalus arundinaceus and the Sedge Warbler A. schoenobaenus. The rapid moult might be an adaptation to a limited period of abundant food which comes to an end at the beginning of the dry season.     

The influence of territory characteristics and food supply on the breeding performance of the Red-backed Shrike (<Emphasis Type="Italic">Lanius collurio</Emphasis>) in an extensively farmed region of eastern Poland

The breeding performance of the Red-backed Shrike (Lanius collurio) in relation to the territory characteristics was investigated. The study was conducted in an area of high agricultural land use, characterised by small field size, a more mosaic habitat and low use of mineral fertilisers in comparison to Western European countries. The influence of habitat structure and composition in the territory on the date of clutch initiation, nest predation and clutch size in the Red-backed Shrike was not found, but such an influence on the number of nestlings was shown. The minimum adequate model explained 18.3% of the variation between territories in nestling’s number. The number of fledglings was positively correlated with the area of pastures, meadows, orchards and fallows within territories, and negatively correlated with length of overhead transmission lines. The number of fledglings was correlated with food abundance within territories, based on to the results from pitfall traps. There was no correlation between territory food abundance and the size of clutch. The presence of pastures, meadows and fallows, which are foraging places, thus seems to be crucial for the protection of the Red-backed Shrike.     

Analysis of stable isotopes in feathers of Red-backed Shrikes ( Lanius collurio ): no evidence for different wintering habitats of males and females

We investigated the stable isotope signatures (δ¹⁵N and δ¹³C) of greater feather covers of male and female Red-backed Shrikes (Lanius collurio) of a southern German population. Male and female birds did not differ in their isotope signatures, thus revealing similar winter grounds for both sexes.