Made it to Cliffe about an hour before high tide, just in time to see many of the waders arrive off the Thames.
Great numbers of Avocet, Dunlin, Black-tailed Godwit, Redshank, Little Egret, Great Crested Grebe, Little Grebe, Black-headed Gull, Black-backed Gull, Herring Gull, Shoveller, Teal, Shelduck, Mallard, some Pintail.
One possible Little Stint actively feeding on the drier sand behind a large group of Dunlin.
Woodpigeon, Stock Dove, Woodpigeon, Robin, Blue Tit, Long-tailed Tit. Some warblers seen, possibly an autumn call of a Chiff-chaff.
It was very nice to see the Golden Plover on the edges of the pools. There were a number of the Grey Plover as well, looking tougher as they so often do, with their heavier bills. However the Golden Plover, Pluvialis apricaria, were my main interest today. These may be breeding in Northern Europe or Russia, but they could be from the uplands of the UK as well. The breeding in the UK might be regarded as somewhat on the edge of its range, and also slightly artificial as upland moorland is largely created by historic land management, but there has been quite a lot of research on the breeding ecology of these gorgeous birds. The UK population could be regarded as at the southern edges of its breeding range and particularly subject to potential warming and drying climate change, which could reduce food sources such as cranefly (Tipulid) larvae. In order to preserve this potentially threatened population, 9Pearce-Higgins, 2011) suggested thart efforts could be made to improve habitat, and thus breeding success, and reduce predation on the other hand.
One very interesting and unexpected feature - the males and females split incubation period in an interesting way: the males incubate during the day, while the females incubate at night.
The research has shown some rather odd features of this species' breeding ecology. When not incubating their eggs on moorland, the adults can often be found on neighbouring agricultural pasture fields rather than moorland, where they are likely to be feeding (perhaps) or resting for about half their time. This is however less true for the males. The average distance moved to the fields was about 2.7 km in the Sunderland study, with females flying further than males. Individual flocks of birds tended to show fairly strong faithfulness to their individual favourite fields, both within a year, and from year to year. Relatively few of the available fields were used for feeding, with those used tending to be large, old, with some cover of rushes Juncus spp., and grazed by sheep. Leatherjackets were possibly the favoured prey.
Although field size did not seem to determine whether fields were occupied or not, field size was correlated with the numbers of birds in an occupied field. Having wet flushes did seem to increase the popularity of a field being chosen, as did the sward kept short by sheep. The nature of the boundary did not seem to have much of an effect, although this might have been expected to have affected ease of predation. The number of molehills, as a proxy for earthworm numbers, was a good indicator of field attractiveness, (according to Whittingham et al, 2000).
Once the eggs hatch, the behaviour of the adults changes, and then they spend much motre time foraging on moorland.
It was estimated that there were about 2,000 pairs breeding in Caithness, of which about half would have been nesting in the Special Protection Area (declared because of the importance of this area for the total breeding population. The fields used while incubating need to be managed appropriately: Management of areas of pasture to maintain their suitability for feeding golden plovers should, in general, avoid ‘improvement’ in the sense typified by agricultural intensification (Wilson et al., 2005). Specifically, the following practices should be avoided: Draining; Application of pesticides to control tipulid larvae (cranefly larvae = leatherjackets); Ploughing and re-seeding with single palatable grass species; Application of inorganic fertilisers; Removal of grazing; Conversion to silage or hay crop.
Based on the apparent preferences of golden plovers, the following characteristics of fields should be maintained: Field size (although enlargement through removal of fences between fields should not have an adverse effect); Poor drainage (as revealed by at least some coverage of Juncus rushes); Multi-species grass community; Grazing regime to maintain a short sward less than 5 cm
Tipulid larvae abundance is also enhanced by the presence of a taller sward during the adult tipulid emergence period ( July – September); this is thought to be because taller grass prevents airborne laying females being blown away by the wind and hence encourages them to lay their eggs in a small area around their emergence site (McCracken et al., 1995; Bignal et al., 1996). Thus a grazing regime whereby livestock is put on to fields in late winter (to create a short sward) but is removed shortly before the adult tipulid emergence period begins in July (to allow a taller sward to develop and retain laying female tipulids) should create favourable conditions for feeding golden plover. In this context, fields used as ‘lambing parks’, especially where ewes and lambs (or other livestock after lambing has finished) are held until mid-June before being hefted to other areas, are likely to be favoured by golden plovers, assuming other field characteristics are compatible.
Clearly these practices should be targeted at those fields already known to be used by plovers, although, as noted earlier, identification and maintenance of suitable ‘alternative’ fields nearby should also be desirable. The proportions of all fields which are used by golden plover are so small (about 3% overall) that it should be feasible to strike a balance between maintaining sufficient suitable fields whilst still being compatible with any intensification deemed as necessary by farmers, although in some holdings the proportion of ‘plover fields’ may be locally greater. Maintenance of fields which are potentially or known to be suitable for golden plover should also benefit several other wader species which appear to have similar preferences.
The chicks obviously feed closer to the nest, and appear in NorthEast England to like patches of mixed heather and grasses, as well as wet areas. Mixed grazing of appropriate intensity to create the vegetation mosaic, as well as stopping up drains to create the wet areas, might therefore be very helpful in aiding their feeding, possibly primarily in Tipulids (according to Whittingham et al, 2001). In Swedish Lapland the pattern differed somewhat according to (Machin et al, 2001), where the chicks fed largely on Coleoptera but also first on Tipulids on more open areas, then switched (as these ran out (?)) to Bibionids in Willow Scrub a bit later, which might also have helped to protect them from predators.
