Habitat use and nesting success of the Great Reed Warbler (Acrocephalus arundinaceus) in different reed habitats in Serbia

Abstract

ABSTRACT.---We surveyed five reed habitats (mining pond, sand pit, large canal, small 1 canal and lowland river) in north-western Vojvodina (Serbia) between 2009-2011 to study 2 habitat use and to estimate nest success in an understudied region of the breeding range of the 3 Great Reed Warbler (Acrocephalus arundinaceus). Data from 174 nests showed that habitat 4 use differed considerably between the habitat types, but was not related to the area of the 5 study site or the reed bed. Higher-than-expected numbers of nests along the small canal and 6 the river suggested that Great Reed Warblers preferred these to other habitats for nesting. 7Habitat use was closely linked to the availability of reed edges and the quality of the reed 8 stand. Overall Mayfield nest success was 43%, slightly lower than in northern and western 9 Europe. Nest success was low along the small and large canal, where brood parasitism by 10Common Cuckoos (Cuculus canorus) and nest predation were high due to nearby tree lines 11 providing perching sites to cuckoos and predators. Nest success was intermediate at the 12 mining pond due to very high predation pressure and adverse weather, and nest success was 13 highest in the sand pit (despite high Cuckoo parasitism) and the river (despite relatively high 14 predation). In conclusion, our results suggest that canals can function as ecological traps, 15 which attract edge-preferring Great Reed Warblers but are highly accessible to predators and 16 brood parasites. In contrast, sand pits can be perceptual traps because they provide good 17 resources for nesting but were less attractive to Great Reed Warblers than other habitats. 18Habitat use in relation to habitat availability thus depends primarily on the availability of reed 19 edges and the quality of the reed stand, whereas nest success also depends on the 20 characteristics of the surroundings and weather conditions.

<p class="NoSpacing1">THE EFFECTS OF WEATHER AND REED MANAGEMENT ON NESTING PARAMETERS OF THE GREAT REED WARBLER, ACROCEPHALUS ARUNDINACEUS (AVES: SYLVIIDAE)

“…two per nest) were similar as in the short-term study of . Furthermore, previous studies confirm similar clutch sizes, number of fledglings and nesting success (ranging from 23.1% to 59.7%) in the Great Reed Warbler in various reed habitats in Central Europe (Beier 1981, Dyrcz 1981, Petro et al 1998, Mérő et al 2015b. found that nesting success was similar in both burnt and non-burnt reed patches.…”

“…In this study, we define the nesting success as the probability that an egg produces a fledgling. The multiplication of the egg and nestling survival rate for the entire incubation and nestling period and the hatching rate resulted in the final nesting success rate, and was then converted to percentages (Mérő et al 2015b). In this study, the hatching rate is defined as the probability that an egg present at hatching time produces a hatchling (Mayfield 1975).…”

Host alarm calls attract the unwanted attention of the brood parasitic common cuckoo

“…The great reed warbler is a typical ‘edge-species’ which prefers to breed on the edge of the reed beds and in the narrow reed-stripes found alongside irrigation channels 47,48 . These high-quality habitats, despite being quickly occupied by early-arriving, large-winged and presumably higher-quality males, are characterized by higher rates of brood parasitism 49–51 . Therefore, irrigation channels function as ecological traps 50,51 and habitats for sink populations, dependent on the influx of naïve individuals from the habitats with low parasitism rates 52 .…”

Adaptation or ecological trap? Altered nest-site selection by Reed Parrotbills after an extreme flood

“…However, they are also very easily flooded by rising tides that can overturn nests (Martijn et al 2010). In addition, reproductive costs may be much larger when a previously suitable habitat experiences a sudden change (like a flood or hurricane) (Mérő et al 2015).…”