Nests are structures that protect eggs and nestlings from the external environment while also serving various other functions in avian life histories. Nest-building behaviour varies between species and habitats, and recent work has highlighted that in areas with high human activity and low availability of natural nest material, birds may use anthropogenic material to construct nests. However, we know relatively little about how nest composition is affected by human presence along urban gradients. Here we examined how nest composition differed between urban and forest populations of blue tits Cyanistes caeruleus, and the impact that variation in nest composition had on reproductive success (clutch size, hatching and fledging success). We found a statistically significant decrease in the weight of moss and grass and an increase in anthropogenic materials in urban compared to forest nests. Nests initiated earlier in the urban environment showed a higher weight of anthropogenic materials. The weight of moss and grass was positively related to fledging success. Our results suggest that the use of anthropogenic material by urban birds might be a maladaptation, and/or that urban birds are constrained in the amount of moss and grass they can find during nest building. Future studies should aim to quantify the availability of material within the environment to test these non-mutually exclusive hypotheses.

This column aims to collect a series of interesting observations, collected without time, space or species limitation, focusing on a limited series of category of interest. In this volume of Avocetta, you will find news items about the following species: Common Merganser (Mergus merganser), White Stork (Ciconia ciconia), Eurasian Stone-curlew (Burhinus oedicnemus), Black Tern (Chlidonias niger), Barn Owl (Tyto alba), Short-eared Owl (Asio flammeus), Pallid Harrier (Circus macrourus), Monk Parakeet (Myiopsitta monachus)/Yellow-legged Gull (Larus michahellis), Zitting Cisticola (Cisticola juncidis), House Martin (Delichon urbicum)/Barn Swallow (Hirundo rustica), Isabelline Wheatear (Oenanthe isabellina).

Review of Drewitt E. 2024. Bird Pellets. A complete photographic guide. Pelagic Publ., London. 250 pp., 685 color photos of mammal and bird skulls, and prey.

Review of Mark A. Colwell and Susan M. Haig., 2020. The Population Ecology and Conservation of Charadrius Plovers. Edited by CRC Press – Taylor & Francis Group, New York, 342 pp

Review of Svensson L., 2023. Identification Guide to European Passerines. Lullula Förlag, Stockholm. 448 pp.

Review of Ollerton J. 2024. Birds & Flowers. An Intimate 50 Million Year Relationship. Pelagic Publishing, London. 312 pp., 28 color plates.

Review of Hume R. 2024. Purposeful Birdwatching. Getting to know birds better. Pelagic Publishing, London. 290 pp., many b/w sketches by the author.

Review of Tveit B.O. 2024. A Birdwatcher’s Guide to Norway. Where, When and How to find Scandinavia’s most sought-after birds. 2nd ed. Ørn Forlag & Pelagic Publishing. 460 pp., many color photos and maps.

Review of Flint P. & Richardson C., 2024. The Birds of Cyprus. An annotated Checklist. BOC Checklist Series: 28. British Ornithologists’ Club. Tring, UK, 492 pp.

Review of Reedman R. 2024. The Vanishing Mew Gull: A Guide to the Bird Names of the Western Palearctic. Pelagic Publishing, London. 378 pp.