Russet Sparrows spot alien chicks from their nests

Abstract

Background:In coevolutionary interactions between brood parasites and their hosts, host parents are under strong selection to evolve defenses against parasitism. Egg rejection is an efficient and common defense against parasitism, although some apparently suitable hosts do not reject cuckoo eggs.Methods: Sparrows Ploceidae are widespread throughout the Old World, and they have a suitable diet for rearing cuckoos, but still they are rarely exploited by brood parasites. To solve such puzzle, we conducted artificial parasitism and cross-fostering experiments in Russet Sparrow (Passer cinnamomeus). Results:The present study showed that Russet Sparrows have no egg recognition ability, but recognize their own nestlings and eject alien chicks or starve them to death. They may use visual cues in chick recognition, although they accept sister species Tree Sparrow (Passer montanus). Conclusions:By rejecting nestlings of foreign species, Russet Sparrows have succeeded to escape from the brood parasitism by cuckoos and other parasites. Our studies shed light on the puzzle why some species are not utilized by cuckoo parasites as hosts.

Hawk mimicry does not reduce attacks of cuckoos by highly aggressive hosts

“…For instance, during the egg laying and incubation stage, many hosts have developed the ability to recognize foreign eggs Brooke 1988, 1989; Brooke and Stokke et al 2002;Stevens 2010, 2011;Yang et al 2016). During the nestling stage, hosts are able to identify foreign chicks (Langmore et al 2003(Langmore et al , 2009Grim 2007;Sato et al 2010;Yang et al 2015;Huo et al 2018). Usually, cuckoos take one host egg during parasitism (Chance 1940;Davies 2000), which means that, once cuckoo eggs are laid, hosts suffer various levels of reproductive losses, even if they perform successful defense behaviors afterwards.…”

Last but not the least: effects of laying sequence on egg color variation and embryonic development of Russet Sparrow (Passer cinnamomeus)

“…Back means eggshell background color, spot means eggshell spot color started (Yom-Tov 1980;Ruxton et al 2001). Although there are many parasitic cuckoo species in the study area (Yang et al 2011(Yang et al , 2012a, despite evidence that cuckoos can parasitize cave-nesting birds and that some cavenesting birds are suitable hosts for cuckoos (Deng 2013;Grim et al 2014;Liang et al 2016), Russet Sparrow was not the host for any type of cuckoos (Huo et al 2018) in this study area and no intra-species parasitism has been observed so far. Hence, the evolution of egg color diversity of Russet Sparrow needs further investigation in the future.…”

“…The Russet Sparrow belongs to the Passeridae family and is mainly found in southern China and the Himalayan region (Summers-Smith 1988). They are year-round residents at this study site, and they build nests in chimney tubes, cavities of stone walls and eaves (Yang et al 2012b;Huo et al 2018). Artificial nest boxes were provided to attract sparrows because entrances to their natural nests are usually too deep and small to allow easy access (see below).…”

“…After a full clutch of eggs had been laid, they were all replaced with model eggs and moved to an incubator together. We did so because Russet Sparrows start their incubation after clutch completion and accept any model eggs in their nests and seem not to show any egg discrimination (Huo et al 2018). After the nestlings hatched, they were returned to their original nests to be raised by their parents.…”

Do swallows (Hirundo daurica) use the visual cue of hatchling down‐feathers to discriminate parasite alien nestlings?

“…Although the evidence for nestling discrimination is rare compared to egg discrimination, at least a dozen of studies have found that host parents can reject alien nestlings by refusing to supply food, nest desertion, or direct ejection (reviewed in Soler et al 1995;Lichtenstein 2001;Payne et al 2001;Grim et al 2003;Langmore et al 2003;Sato et al 2009;Tokue & Ueda 2010;Yang et al 2015b;Grim 2017;Huo et al 2018). Nevertheless, a few studies have revealed the mechanism underlying this discrimination toward foreign nestlings (Table 1).…”