Tits as bryologists: patterns of bryophyte use in nests of three species cohabiting a primeval forest

Abstract

Numerous birds use bryophytes as nest construction material but the species used and their biology remain largely unknown. Therefore, questions related to the selectivity of birds in their bryophyte use, and why they use/ignore particular species, remain unanswered. We studied the composition of bryophytes, including both mosses (Bryophyta) and liverworts (Marchantiophyta), in nests of Marsh Tit Poecile palustris, Blue Tit Cyanistes caeruleus, and Great Tit Parus major breeding sympatrically in tree cavities in pristine patches of the Białowieża National Park, Poland. We checked whether the bryophyte composition of the nests differed, compared usage of different bryophytes with their availability in the surroundings (10 m radius) of the tree cavities, and looked for characteristics that may have resulted in their selection as nesting material. The birds appeared to be highly selective; of 54 bryophyte species found near cavities, 21 were never used. Individual nests contained 4.0-5.5 bryophyte species on average, and only 2.3-2.7 species exceeded 5% of the total bryophyte volume. In each tit species the three most abundantly used bryophytes belonged to mosses and comprised ca. 80-89% of the total bryophyte volume. All of the tits utilized pleurocarpous bryophytes, growing as wefts, mats or pendants mostly on tree trunks. Simulations of plucking showed that the mosses employed as nest constituents yielded larger bundles with longer shoots when plucked. The tit species differed in the sets of bryophyte species collected. Great Tit nests contained an almost completely different assemblage of mosses from that used by Marsh and Blue Tits. This variation was related to the varying mass of their broods; more robust mosses provided support for heavier broods of Great Tits, while the finest moss species were sufficient to form a cushion for the much lighter Marsh Tit broods. Keywords

Geographical location affects size and materials used in the construction of European Pied Flycatcher (Ficedula hypoleuca) nests

“…Whilst it was not clear what significance these differences had for nest function in this species, it seemed that, contrary to reports of selection of very specific nest materials (e.g. Wesołowski and Wierzcholska 2018), the choice of materials used in nest construction by Pied Flycatchers was opportunistic, as has been observed previously in tit species (Surgey et al 2012). Pied Flycatchers in Lancashire seemed to select the types of leaves on their availability within the bird's territory immediately outside their nestbox.…”

“…Birds may be specifically selecting materials for key roles in the nest, as has been observed in the structural characteristics of woody materials used in thrush (Turdidae) and finch (Fringillidae) nests (Biddle et al 2017(Biddle et al , 2018b. Birds may select moss because it absorbs water (Wesołowski et al 2002), or provides structural support (Wesołowski and Wierzcholska 2018), or could trap more air in the nest walls (Deeming and Biddle 2015). These roles may be more important in the colder, and/or wetter north and west of Great Britain, where moss prevails in Pied Flycatcher nests.…”

“…These roles may be more important in the colder, and/or wetter north and west of Great Britain, where moss prevails in Pied Flycatcher nests. However, use of bryophytes in tit nests in Poland did not reflect the availability of species in the nesting locality but rather the birds seemed to be selecting the bryophyte species based on the structural rigidity of its stem (Wesołowski and Wierzcholska 2018). Leaves and bark, used in more southerly locations, may not absorb as much water as moss (Biddle et al unpublished) but may still provide structural support that would trap air in the nest walls.…”

“…Various species seem to use other materials for different reasons. The inclusion of bryophytes in nest by various species of tit (Paridae) appears to be very selective and not to reflect water absorptive properties as was previously thought (Wesołowski et al 2002) but rather indicates the degree of support offered by the stems of the different moss species used (Wesołowski and Wierzcholska 2018). Inclusion of white anthropogenic materials in Black Kite (Milvus migrans) nests has been interpreted as sign of bird fitness (Sergio et al 2011).…”

Wählerisch für den Nachwuchs

“…Im Urwald von Bialowieza in Ostpolen haben Forstbiologen den Meisen in ihre Bruthöhlen geschaut . Das Ergebnis: Blau‐ ( Cyanistes caeruleus, Abbildung und ), Sumpf‐ ( Poecile palustris ) und Kohlmeisen ( Parus major ) erwiesen sich als Moosspezialisten, die genau auswählen, wie sie ihre Kinderstuben gestalten.…”