The Behavioural Ecology, Local Population Dynamics and Conservation of the Bearded Reedling <i>Panurus Biarmicus</i> in “El Hondo Natural Park” (SE Spain)

Abstract

Abstract:The behavioural ecology of the Bearded Reedling Panurus biarmicus in wild using data available from mistnetting has received little attention. One of such aspects is to evaluate if flock composition and structure vary among reed successional stages and facilities dispersal among near wetlands in small and semi-isolated populations by analysing mistnetting capture events. This study shows that mist-netting events comprised catches of solitary birds or small groups in samples from small to moderate size. Overall mean frequency of each flock result in a population of low aggregation at low densities and being lower than reported from bigger central Spanish populations. A majority of birds of these flocks are "transients", characterized by have shorter wing lengths and smaller body masses compared to "residents", which attain higher body masses and longer wing lengths. Residents have the ability to settle in unmanaged sparse habitats in the periphery of the wetlands and the possibility to undertake longer flights outside wetlands is greater due to a higher condition and performance. Since a high overnight mass loss of birds has been verified in this study, I hypothesize that Bearded Reedlings move in short-times elapsed from sunset (before arriving at the roosts) to sunrise, so earlier surveys carried out in wetlands might give inadequate results to monitoring Bearded Reedling's populations, demanding alternative methods to survey them properly. Due to the occurrence of such residents, the importance of saltmarshes with reed sparse-patches in the periphery of wetlands results in a key factor for the dispersal of this species.

Are cleared reeds Phragmites australis growing inside bush areas good for the stop-over of small birds?

“…Breeding territories of Grasshopper warblers in scrub's Salix spp grasslands in colder climates of Northern Europa support major quantities of invertebrates than in optimal (dense) habitats and they are more feasible for feeding in suboptimal areas, 11 With reference to Turkestan-Mediterranean small reed birds, the Mustached Warbler Acrocephalus melanopogon, is noted a trend to an increase of ringing captures in cleared reeds from last decade up to current years in wetlands of Southern Iberia (Peiró pers data) probably due to novel prey invertebrates, extinct in dense areas or due to effects of climate change. The functionality in the use of such suboptimal habitats is based in that some morphological traits, 12,13 are intra-specifically dependent in these areas, in the form that, in spite of major abundance of birds in optimal habitats, older birds are able to enhance suboptimal habitats optimally, since longer wing-lengths abilities for faster flights, favoring dispersal and major habitat occupation. 14−16…”

“…Due to the massive destruction of reed-beds in wetlands from the past centuries, 17 the remnants of reeds in early transitional stages is of importance for the stop-over of many passerines, many of them generalists migrants, and also other highly specialists with an endangered status. 12 It's important to keep connections with dense reeds in order to create a mosaic of a dynamic wetland plant system to facility the stop-over of migrants and the dispersal of sedentary species. [18][19][20][21]…”

Bearded Reedling (Panurus biarmicus): the biology of a remarkable bird – a review of the recent literature

“…Habitat selection may change seasonally among different life-history stages, such as breeding, wintering or dispersing, and even within a single stage depending on the activity (nesting vs. foraging) or between individuals of different body conditions (Hoi & Hoi 2001, Trnka & Prokop 2006, Saygili et al 2013, Peiró 2017. During the breeding season, reedlings prefer to forage in recently grazed or cut stands of reed, where there is higher availability of food and better foraging conditions due to lower vegetation cover.…”

“…The cryptic lifestyle of the reedlings, the lack of territories and their inhomogeneous breeding distribution make it challenging to estimate their abundance correctly (Hoi & Hoi 2001, Surmacki 2003, Vadász et al 2011, Peiró 2013, Dadam et al 2014, Malzer 2017. Systematic ringing and point counts from elevated observation points may yield adequate data, although the applicability of these methods may largely depend on the specific local circumstances and the timing of the census over the season and within a day , Malzer 2017, and they are prone to the presence of transients in the population (Peiró 2017). Estimating breeding efforts directly may provide the most direct estimates of the nesting populations (Wawrzyniak & Sohns 1986, Wilson & Peach 2006, although this requires significant efforts due to the limited accessibility of nesting sites of the species.…”