Zoodiversity_02_2020.indb UDC 598.288.5(477.75) VARIATION IN BLACKBIRD, TURDUS MERULA (PASSERIFORMES, TURDIDAE), NEST CHARACTERISTICS IN URBAN AND SUBURBAN LOCALITIES IN CRIMEA V. M. Kucherenko, A. V. Ivanovskaya Taurida National V.I. Vernadsky University, 95004, Prospect Vernadskogo, 4, Simferopol, Crimea Republic, Ukraine E-mail: zookuch@ukr.net Variation in Common Blackbird, Turdus merula (Passeriformes, Turdidae), Nest Characteristics in Urban and Suburban Localities in Crimea. Kucherenko, V. M., Ivanovskaya, A. V. — Blackbird Turdus merula is a model species for studying the impact of environmental factors on the form and structure of nests. In the middle of XX, this species began to expand its range into the artifi cial forests of the Ukrainian steppe zone. Th is expansion may have led to changes in bird behaviour, including changes in nest construction choices (e.g., nest shape, size, location and building materials). In this study, we investigated Blackbird nest diversity (i. e., size, volume, and composition) in the park of Simferopol (a city in Crimea, South Ukraine) and in an artifi cial forest located nearby. We found a signifi cant inverse relationship between nest placement height and external nest diameter. External nest depth was greater in the forest than in the park. Th is diff erence refl ects the variation in plant life form between the sites. More specifi cally, nests in trees have signifi cantly greater external depth than the nests located on shrubs. Most nests in both urban and suburban localities contained natural and anthropogenic materials; there was no signifi cant diff erence in component types between sites. In general, the anthropogenic materials played a decorative role and also served as camoufl age. K e y w o r d s : Blackbird, Turdus merula, nest morphology, size, Crimea. Introduction Nest building is a taxonomically widespread activity, with birds, mammals, reptiles, fi sh, and insects all constructing nests of some type in which to lay eggs or raise off spring (Hansell, 2000). Dawkins (1982) argues that just as there are specifi c genes for body form or eye colour, there must be genes whose phenotypic expression is apparent in the architecture of a nest or web. Even within taxa, there is a great deal of variation in nest design; in birds, nests range from the small but elaborate cup-shaped nests built by passerines to the huge mounds built by megapodes (Hansell, 2000). Th e shape and placement of nests are specifi c; that is, individuals can identify the nests of their own species based on those nests’ morphological features. Empirical studies examining the design and function of bird nests are not randomly distributed with respect to ecology; the vast majority of studies involve small hole-nesting passerines, which breed inside nestboxes (Mainwaring at al., 2014 a). Nonetheless, our understanding of the design and function of bird nests has increased considerably in recent years. In particular, evidence now suggests that nests have four functions that are not mutually exclusive. Moreover, bird nest designs are far more sophisticated than previously realized; nests are multifunctional structures that have important fi tness consequences for the builders (Biddle et al., 2015; Mainwaring et al., 2014 a). Th e body of knowledge regarding the factors that aff ect nesting variables (e. g., nest placement, nesting duration, nest construction period, and clutch size) is still far from complete, especially for bird species that built open-cup nests (Mainwaring et al., 2014 b). Blackbirds Turdus merula are a model species for studying the impact of environmental factors on the form and structure of nests because the species is widespread and common, and its nests are relatively easy to fi nd. Blackbirds build open-cup nests that consist of a bulky cup of twigs, dry grasses, moss, stalks, and other vegetative material plastered on the inside with mud or muddy leaves. Th e nests are completed with a lining of fi ne grass, thin dead stems, or rootlets (Cramp, 1988; Mainwaring et al., 2014 b). Zoodiversity, 54(2): 157–162, 2020 DOI 10.15407/zoo2020.02.157 158 V. M. Kucherenko, A. V. Ivanovskaya In the middle of XX T. merula began to expand its range into the artifi cial forests of the Ukrainian steppe zone (Tsvelykh, 2017). By the end of XX, Blackbird occupied the Simferopol (Crimea, South Ukraine) (Treschev & Kupsha, 1986). Range changes aff ect bird behaviour, including nest construction choices; birds may alter their nest size, shape, location, and building materials. Th ese changes can be assessed not only by observation but also by studying nest construction. Th us, the aim of this study was to compare the diversity of blackbird nest designs between diff erent urban and suburban localities and to assess the relationship between nest construction characteristics and environmental factors. Material and methods Our research was conducted from 2016 to 2018 at two study sites: the Salgirka City Park (44°56' N, 34°07' E) and the artifi cial forest on the Simferopol Reservoir (44°56' N, 34°09' E). Salgirka City Park (about 33 ha) is located in the southern part of Simferopol. It is constantly visited by people and surrounded by roads, streets, and buildings. Th e park’s trees are mostly deciduous; however, 20 % are 50–70 year-old coniferous trees. A shrub layer consisting predominantly of Rosa canina, Clematis sp. covers about 20 % of the park. Th e artifi cial forest on the Simferopol Reservoir contains 60–70 year-old trees, of which about 80 % are coniferous and 20 % are deciduous. Th e shrub layer near the reservoir is very scant and consists of Rosa canina and Prunus spinosa. Th e distance between these two sites is about 3 km. Blackbird nests were collected aft er nest abandonment at the end of the breeding season. Prior to analysis, the nests were stored for at least several months at approximately room temperature and humidity. We measured six aspects of nest morphology: external nest diameter, internal nest-cup diameter, external nest depth, internal nest-cup depth, volume, and weighed (Hansell, 2000; Mainwaring et al., 2014 b). Th e volume of the nest cup was determined by placing polyethylene under the nest-cup and fi lling it with water. Aft er measuring, the samples were decomposed so that their structural components could be studied. We identifi ed three main nest regions: outer nest (loosely arranged, generally not interwoven), structural wall (sometimes interwoven, typically incorporating mud, cup-like shape) and cup lining (interwoven structure, cup-like shape) (Biddle et al., 2014). Each structural region was carefully deconstructed, taking particular care to avoid damaging any of the individual elements. We e stimated the number of component types in each nest layers. T-tests and Wilcoxon tests were used to determine whether signifi cant diff erences in nest morphology were between the two study sites. Th e normality of each variable’s distribution was tested using the Shapiro- Wilk test. We carry out all analyses in R version 3.6.0 (R Core Team 2017). Results and discussion Prev ious studies have reported a relationship between nests placement height and nest predations rates. More specifi cally, nests located higher were more oft en attacked by avian predators; nest places near the ground were safer despite being greater risk from a range of mammalian predators (Piper & Catterall, 2004; Mainwaring et al., 2014 a). In our study, nest placement height not diff ered between the park and forest (t = 0.02, p < 0.98) likely because of the same variation in mammalian and avian predation rates in both places. Th ere was a signifi cant inverse relationship between nest placement height and external nest diameter (r = – 0.44, p < 0.05) (fi g. 1). According to Mainwaring & Hartley (2013), nest building is energetically expensive, and birds build smaller nests at greater heights above the ground in order to compensate for these costs. Two characteristic of nest construction (i. e., mass and volume) have a clear infl uence on energy costs. However, in our study, there were no signifi cant correlations between nest height and nest volume, mass, external depth, or internal depth. Th us, the energy costs associated with nest construction did not aff ect placement height. On the other hand, nest size is determined by a nest’s outer diameter. It can be concluded that birds tend to reduce the external nest diameter in order to decrease the visibility of nests located high above the ground. Th is hypothesis fi ts with the mammalian and avian predation pressure outlined above. Th e main predators of common blackbird nests at the study sites were Magpies (Pica pica) and Jays (Garrulus glandarius). Reduction in visibility make nests safer by diminishing the risk of attack from avian predators. In addition, we determined that the external nest depth was grater in the forest than in the park (t = 4.64, p < 0.01, t-test) (table 1, fi g. 2). Th is can be explained by diff ering composition of tree species that birds use to build nests in the park compared with the forest. It was also noted that nests in the forest were more oft en located on trees, while in the park they were more common on shrubs. In contrast to our research, urban and 159 Variation in Common Blackbird (Turdus merula) Nest Characteristics… park-dwelling blackbird in Turkey are more likely to build nests in trees, and in forest they generally build on shrubs (Karakaya & Arikan, 2015). We checked whether plant type aff ects external depth of the nest. We found that nest s in trees had a signifi cantly greater external depth than nests located on shrubs (t = 3.198, p < 0.05, t-test) (fi g. 3). It appears that this occurs because nest location relative to the trunk varies with plant type. In trees, nests were more oft en located near the trunk, likely because placing the nest near the trunk increases the area of contact between the nest and its attachment site. When the nest lies on a shrub branch, the support is located below the nest, and this provides a secure mount that does not requ ire additional design solutions. Th ere were no signifi cant diff erences in other nest size characteristics (i.e., volume, external diameter and internal diameter) between sites. Th ree main cup-shaped regions were identifi ed: outer nest (loosely arranged, generally not interwoven), structural wall (sometimes interwoven, typically incorporating mud, cup-like) and cup lining (interwoven structure, cup-like shape) (Biddle et al., 2015). Th e number of component types in each nest layer varied; there were 4–8 component types in the outer layer, 4–9 component types in the middle layer, and 2–6 component types in the inner layer (table 2, fi g. 4, A–C). We assumed that the environment in the city was more diverse; therefore, we further hypothesized that the number of component types in the nests at the park would be higher Fig. 1. Th e relation between external nest diameter and nest placement height (N = 27). T a b l e 1 . Blackbird nest characteristics in the park and in the forest Site Height placement, cm External nest diameter, cm. Internal nest diameter, cm External nest depth, cm Internal nest depth, cm Nest cup volume, ml Mass, g N X ± SE N X ± SE N X ± SE N X ± SE N X ± SE N X ± SE N X ± SE Park 32 183.7 ± 10.2 15 17.9 ± 0.4 15 11.0 ± 0.3 15 9.9 ± 0.2 15 6.0 ± 0.2 10 227.2 ± 20.2 10 175.3 ± 19.9 Forest 29 169.1 ± 10.6 10 17.9 ± 0.4 10 10.4 ± 0.2 10 11.8 ± 0.3 10 5.9 ± 0.2 10 236.5 ± 15 10 171.2 ± 16.3 160 V. M. Kucherenko, A. V. Ivanovskaya than in nests in the forest. However, there was no signifi cant diff erence in the number of component types in any layers between the park and forest (Wilcoxon test, p > 0.05). A previous study showed that the global pattern of debris incorporation in bird nests refl ects anthropogenic pressure (Jagiello et al., 2019). In our survey, only 5 nests out of 21 did not contain anthropogenic materials; of those, four were located in a suburban area (forest), and one was located in an urban locality (park). Pieces of polyethylene, paper towels, and wet wipes were found in the nests. It is likely that these anthropogenic materials played a decorative role and helped better camoufl age the nests. Th e outer layer of nests oft en contained moss, but in half of the nests from the park, moss was replaced by clematis stems (Clematis sp.). Fig. 2. Th e diff erences in external depth between Blackbird nests in the park (N = 15) and forest (N = 10) Fig. 3. Th e diff erences in external depth between Blackbird nest in tree (N = 12) and shrubs (N = 15). T a b l e 2 . Types of components used in the structural layers of Blackbird nests in the park (N = 10) and in the forest (N = 10) Types of components Outer layer Medium layer Inner layer park forest park forest park forest Moss + + + + + + Lichen - + – – – – Anthropogenic materials + + + + + + Stems of perennial grasses + + + + + + Stems of annual plants + + + + + + Tree bark + + + + + + Leaves + + + + + + Roots + + + + + + Stems of shrubs and trees + + + + + + Mud – – + + + + Stones – – + + – – 161 Variation in Common Blackbird (Turdus merula) Nest Characteristics… Conclusion Blackbird nest structure depends on various environmental conditions. Th is demonstrates the ecological plasticity of the species. We found a signifi cant inverse relationship between nest placement height and external nest diameter. In contrast to the assumption that birds tend to reduce energy costs when building nests higher above the ground (Mainwaring & Hartley, 2013), in our opinion, birds tend to reduce the visual size of nests located high above the ground to avoid avian predators. Our data broadens the knowledge about the patterns of change in nest morphology. Previous study showed, open-cups nesting birds systematically vary the design of their nest to respond to large scale latitudinal variation of spring temperatures (Mainwaring et al., 2014 b). We found 0 1 2 3 4 5 2 3 4 5 6 nu m be r o f n es ts number of types of components park forest 0 1 2 3 4 5 4 5 6 7 8 9 nu m be r o f n es ts number of types of components park forest 0 2 4 6 8 4 5 6 7 8 nu m be r o f n es ts number of types of components park forest Fig. 4. Number of component types in each nest layer: A — Outer layer, B — Medium layer, C — inner layer. B C A 162 V. M. Kucherenko, A. V. Ivanovskaya that external nest depth was greater in the forest than in the park. Th is diff erence refl ects the variation in plant life form between the sites. More specifi cally, nests in trees have signifi cantly greater external depth than nests located on shrubs. Most nests in both urban and suburban localities contained natural and anthropogenic materials; there was no signifi cant diff erence in component types between sites. In general, the anthropogenic materials played a decorative role and also served as camoufl age. References Biddle, L. E., Deeming, D. C. & Goodman, A. M. 2015. Morphology and biomechanics of the nests of the Common Blackbird Turdus merula. Bird Study, 62 (1), 1–9. Doi: 10.1080/00063657.2014.988119 Cramp. S. 1988. Th e birds of the Western Palearctic. Vol. 5: Tyrant fl ycatchers to thrushes. Oxford Univ. Press., Oxford, 1–1163. Dawkins, R. 1982. Th e Extended phenotype. Oxford, WH Freeman, 1–295. Hansell, M. H. 2000. Bird Nests and construction behaviour. Cambridge University Press., Cambridge, 1–280. Jagiello, S., Dilewsky, Ł., Tobolka, M., Aguirre, J. I. 2019. Life in a polluted world: A global review of anthropogenic materials in bird nests. Environm. Pollut., 251, 717–722. Doi: 10.1016/j.envpol.2019.05.028 Karakaya, M., Arikan, K. 2015. Th e nest-site characteristics of the forest population of common blackbird (Turdus merula) in Eskişehir, Turkey. Turkish journal of zoology, 39 (2), 295–299. Doi: 10.3906/zoo-1401- 36 Mainwaring, M. C., Hartley, I. R. 2013. Th e energetic costs of nest building in birds. Avian. Biol. Res., 6, 12–17. Doi: 10.3184/175815512X13528994072997 Mainwaring, M. C., Hartley, I. R., Lambrechts, M. M. & Deeming, C. D. 2014 a. Th e design and function of bird’ nest. Ecol. evol. 20 (4), 3909–3928. Doi: 10.1002/ece3.1054 Mainwaring, M. C., Deeming, C. D., Jones, C. I., Hartley, I. R. 2014 b. Adaptive latitudinal variation in Common Blackbirds Turdus merula nest characteristic. Ecol. evol. 4 (6), 851–861. Doi: 10.1002/ece3.952 Piper, S. D., Catterall, C. P. 2004. Eff ects of edge type and nest height on predation of artifi cial nests within subtropical Australian eucalypt forests. Forest Ecol. Manag. 203, 361–372. Doi: 10.1016/j.foreco.2004.08.005 Treschev V. V., Kupsha, A. S 1986. To the study of the avifauna of Simferopol. In: Apostolov, L. G., Mishnev, V. G., eds. Prirodoohrannie issledovania ecosystem Gornogo Kryma. Simferopol, USSR, SGU Press, 136–139 [In Russian]. Tsvelykh, A. N. 2017. Th e Expansion of the Blackbird, Turdus merula (Passeriformes, Muscicapidae), in the Steppe Zone of Ukraine. Vestnik Zoologii, 51 (5), 413–420. Doi: 10.1515/vzoo-2017-0049 Wysocki, D., Jankowiak, Ł., Greño, J. L., Cichocka, A., Sondej, I. & Michalska, B. 2015. Factors aff ecting nest size in a population of Blackbirds Turdus merula. Bird Study, 62 (2), 208–216. Doi: 10.1080/00063657.2015.1030722 Received 22 August 2019 Accepted 25 February 2020 << /ASCII85EncodePages false /AllowTransparency false /AutoPositionEPSFiles true /AutoRotatePages /None /Binding /Left /CalGrayProfile (Dot Gain 20%) /CalRGBProfile (sRGB IEC61966-2.1) /CalCMYKProfile (U.S. Web Coated \050SWOP\051 v2) /sRGBProfile (sRGB IEC61966-2.1) /CannotEmbedFontPolicy /Error /CompatibilityLevel 1.4 /CompressObjects /Tags /CompressPages true /ConvertImagesToIndexed true /PassThroughJPEGImages true /CreateJobTicket false /DefaultRenderingIntent /Default /DetectBlends true /DetectCurves 0.0000 /ColorConversionStrategy /CMYK /DoThumbnails false /EmbedAllFonts true /EmbedOpenType false /ParseICCProfilesInComments true /EmbedJobOptions true /DSCReportingLevel 0 /EmitDSCWarnings false /EndPage -1 /ImageMemory 1048576 /LockDistillerParams false /MaxSubsetPct 100 /Optimize true /OPM 1 /ParseDSCComments true /ParseDSCCommentsForDocInfo true /PreserveCopyPage true /PreserveDICMYKValues true /PreserveEPSInfo true /PreserveFlatness true /PreserveHalftoneInfo false /PreserveOPIComments true /PreserveOverprintSettings true /StartPage 1 /SubsetFonts true /TransferFunctionInfo /Apply /UCRandBGInfo /Preserve /UsePrologue false /ColorSettingsFile () /AlwaysEmbed [ true ] /NeverEmbed [ true ] /AntiAliasColorImages false /CropColorImages true /ColorImageMinResolution 300 /ColorImageMinResolutionPolicy /OK /DownsampleColorImages true /ColorImageDownsampleType /Bicubic /ColorImageResolution 300 /ColorImageDepth -1 /ColorImageMinDownsampleDepth 1 /ColorImageDownsampleThreshold 1.50000 /EncodeColorImages true /ColorImageFilter /DCTEncode /AutoFilterColorImages true /ColorImageAutoFilterStrategy /JPEG /ColorACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /ColorImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000ColorACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000ColorImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /GrayImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000GrayACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000GrayImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict << /K -1 >> /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False /CreateJDFFile false /Description << /ARA /BGR /CHS /CHT /CZE /DAN /DEU /ESP /ETI /FRA /GRE /HEB /HRV (Za stvaranje Adobe PDF dokumenata najpogodnijih za visokokvalitetni ispis prije tiskanja koristite ove postavke. 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