Comparative breeding biology of Hen Harrier and Montagu’s Harrier: an 8‐year study in north‐eastern France

Abstract

Hen and Montagu’s Harriers breed in the same cultivated areas of eastern France. We present data from an extensive study conducted in three adjacent areas where 757 nests of the two harriers were monitored between 1993 and 2000, with the aim of comparing the breeding ecology of these two species and to evaluate their possible future trends. Breeding habitat for harriers consisted nearly exclusively of winter cereals, causing great conservation concern in this intensively farmed region. The Hen Harrier was almost absent from two of the study areas. This species showed significantly larger clutch size and higher breeding success than the Montagu’s Harrier, and an earlier breeding phenology. It was thus less adversely affected by harvesting activities than Montagu’s Harrier. Both species showed a reduced breeding success with increasing laying date. There was a large diet overlap between the two species, possibly leading to competitive interactions. Overall, the Montagu’s Harrier should be considered as the more vulnerable of the two species, necessitating conservation measures, such as protection of nests from early harvesting activities. Nevertheless, to maintain both species in agricultural habitats, farming practices that preserve sufficient food should also be promoted.

Breeding biology of Montagu’s Harrier Circus pygargus in north-central Kazakhstan

“…Interestingly, we found no significant interannual variations in clutch size or the proportion of breeding first-year females, despite strong variations in the abundance of one of their prey, voles. This is in contrast to that observed in western European vole-eating populations (Salamolard et al 2000;Millon et al 2002;Koks et al 2007). …”

“…Another interesting result was the absence of seasonal decline in clutch size, as reported in many other studies on Montagu´s harrier (Castaño, 1995;Salamolard, 1998;Millon et al 2002;Koks et al 2007), other raptors (Newton & Marquiss, 1984;Korpimäki & Wiehn, 1998;Mougeot & Bretagnolle, 2006) and more generally in bird species (Arnold et al 2004).…”

Development of New Microsatellite (STR) Markers for Montagu’s Harrier (Circus pygargus) via 454 Shot-Gun Pyrosequencing

“…According to BirdLife International (2013), the global population of Montagu's harrier consisting of 50-75,000 breeding pairs is classified as "least concern". Nevertheless, many European populations of Montagu's harrier suffer significant losses, mainly due to human activities on farmland [8][9][10]. Without protection, approximately 60% of nestlings of this ground-breeding bird would be killed during harvest [5].…”

“…de May and beginning of June). Intensive nest protection is usually the only way to enable breeding success [9,12,13]. A second critical factor for Montagu's harrier is the continuous decline in prey availability due to the destruction of many suitable hunting grounds, like fallows and field edges [14,15].…”

Timing of breeding, habitat preference and reproductive success of marsh harriers (Circus aeruginosus)

“…Several recent studies have described a few cases of successful nesting in quite dissimilar habitats, in trees or bushes (Kunstmüller & Hlaváč 1988;Koks 1994;Ruxová 1998) although in general harriers nests "exclusively" on the ground (Del Hoyo et al 1994;Forsman 1999). The life history of the species in more stable marshlands was studied in Western (Schipper 1979;Underhill-Day 1984;Dijkstra & Zijlstra 1997;Bavoux et al 1998) and Central Europe (Witkowski 1989;Báldi & Kisbenedek 1998), but only a few studies assessed the importance of timing of breeding and reproductive output in relationship with preference of heterogeneous habitat (Millon et al 2002;Němečková 2005). The leaves and stems of reedbed plants provide substratum for nest placement (Witkowski 1989;Fernández 1992).…”