Redstart & Wood Warbler Survey
The Redstart (Phoenicurus phoenicurus) and the Wood Warbler (Phylloscapus sibilatrix) are both rare migrants and breeders in Ireland. They are amber listed, meaning they are species of medium conservation concern. Both species are closely associated with the oakwoods of County Wicklow. Glendalough, Glenmalure, Luggala, and Rathdrum have some of the best stands of sessile oakwood in the county and all have regular sightings.
In 2007, nestboxes were put up in the Glendalough oakwoods and Clara Vale Nature Reserve for redstart, by NPWS staff. The species is known to have adapted well to nestboxes in Wales. In 2008 the National Park staff started to survey Redstarts and Wood Warblers with a view to obtaining baseline data and details on their relative abundance.
Redstart
The redstart is a declining species throughout Europe. This decline may be due to changing rainfall patterns in the Sahel, which is affecting wetlands for migratory birds moving along the African – Eurasian flyways. Other possible contributory factors may include modern forestry causing a decrease in nesting holes and increased competition for natural nesting holes from other species such as the tit family.
The redstart is a rare migrant to Ireland. Redstarts are found in Ireland between April and September, with the peak time to hear their calls from mid-May to mid-June. They breed in deciduous and mixed woodland, and nests in tree holes. They feed on insects, in particular, beetle larvae, butterflies and spiders. Males are colourful, and display the red tail and under-wing, when trying to attract a female. The female lays 6-7 eggs, incubation is 13-14 days and the young fledge after 16-17 days. They can have up to two broods in one season. They breed at one year. The maximum recorded age is 6 years and 9 months.
Wood Warbler
The wood warbler is the brightest and biggest of the 3 leaf warblers that occur in Ireland. (The other two are the chiff chaff and the willow warbler.) It is considered, a rare migrant in Ireland, arriving in mid-April until August. They winter in sub-Saharan Africa. Its breeding distribution stretches from the Pyrenees Mountain range, north to Lapland, south to southern Italy and east to the Balkan peninsula. Its range in Ireland is most likely limited by lack of suitable forests. They can be found in mixed woodland and tend to like oak forest with minimal undergrowth. They require a shady closed canopy for foraging, sparse low ground for nesting, and a lower canopy for singing and display. This combination means that they will occupy different forest types. They feed on insects and other invertebrates. Wood warblers have a low site tenacity, changing its breeding areas from year to year, which can result in localised fluctuations. Breeding in Ireland was first proven in 1968, in Co.Wicklow.
Males arrive back after winter first to set up territories, often in the same area that they were raised. The singing male flies from branch to branch within his territory. The females build domed nests, usually made of leaves, grass, moss and bracken and lined with fine grass and hair. The female lays 5-7 light blue eggs, incubation usually lasts about 13 days, juveniles fledge after about 13 days. The female can have up to two broods in one season.
The Survey
In 2008, four sites were surveyed within the National Park and adjoining Nature Reserve - Glendalough woods, Derrybawn woods, Camaderry Woods, and Rathdrum Rd woods. It was hoped to visit each site 4 times between 15th April and 15th June, but in the event, two sites only received 3 visits, and one site only received one visit. Each visit involved walking a transect between first light and 9.30 am, recording calls.
No redstarts were heard at any of the sites during the survey visits. In fact, according to Birdwatch Ireland, 2008 was not a good year for redstarts. Redstarts were only heard by their members calling once in Glendalough and not at all in Rathdrum Woods during the nesting season.
Wood Warblers were more in evidence, and were recorded by surveyors on four of the visits.
It is hoped to continue this survey in future years, to give staff a greater idea of the population dynamics within the Park. Ideally, the survey will be broadened to include other woods within the Park.