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SITES
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Scarlino, Italy Birds To date, 47 species of birds have been recorded on the Tioxide site
at Scarlino Birds are not only diverse on the Scarlino site, they are also numerous - no doubt reflecting the varied habitats present and the high level of protection given by the security procedures of the industrial site. Outside of protected areas hunting pressure on birds and other wildlife is intense. There are 100,000 hunters in Tuscany (Gemsbol 1989) and over 2 million hunters in Italy as a whole. This represents a density of eight hunters per square kilometre (Cassola 1979). Virtually all unprotected wildlife habitats are shot over several times each week during a long hunting season (MacDonald & Mason 1983). Consequently, protected industrial areas such as the Tioxide site at Scarlino are of national importance. They compliment officially protected areas such as National Parks and reserves managed by international conservation organisations like the World Wide Fund for Nature (WWF). Although some hunting is carried out on and around the Tioxide property, as evident by spent cartridge cases on the site, the problem does not appear to be acute. During intensive observations from 26-28 May 1998 in the wilder parts of the site no hunting was observed. Further birds such as Turtle Doves (a particularly favourite quarry bird) were numerous and were not shy, suggesting that they had not been disturbed by hunters. A number of birds have already been mentioned in the general review of the site’s wildlife habitats. In this section some of the significant species present are discussed in more detail, with particular reference to their conservation importance and status. Herons In order to ensure that the site remains suitable for all of the heron species already present, and if possible attracts other species found in adjacent areas, then the correct diversity of habitats will have to be maintained. A variety of food items are taken by each of the five herons occurring on the site, and although there is some overlap each species has particular preferences. There is therefore considerable ecological separation of the species especially as to the size of the food items taken. Squacco Heron and Little Egret When hunting active prey, such as fish, Little Egrets also employ the “open-wing method”. They run swiftly zigzagging through shallow water and raising their legs very high. There are frequent wing beats and even leaps into the air. Prey is again caught by a swift lunge with the bill. More detailed descriptions of Little Egret feeding behaviour, including unusual foraging methods, are given by Voisin (1991) and Cramp et al. (1977). Even within the same geographical area various groups of Little Egrets can take different prey depending on local availability. Nevertheless in studies of various populations in France fish were always the most important food item, accounting for up to 83% of the diet (Vorsin 1991). The prey size taken by Little Egrets is usually fish between 2-6 cm, and the food spectrum based on studies in the Camargue, Southern France, is shown in Figure 24 (Vorsin 1991). Mullets appear to be an important item of the birds diet in France and the situation in Italy is probably very similar. The Mosquito fish (Gambusia) is a North American species introduced into the Mediterranean region to control mosquitoes. Squacco Heron is the rarest of the European herons. In western Europe it is most common in Italy with an estimated breeding population of ca. 1000 pairs in 1992 (Kushlan & Hafner 2000). The species is highly dependent on freshwater habitats, preferring permanently water- logged and much more vegetated wetlands than Little Egret. The birds either feed in shallow water along the edge of reedbeds or even amongst reeds or other aquatic plants. They avoid brackish water probably because such sites are less vegetated. The birds usually hunt by standing motionless, often in a crouched position, or less frequently by slowly walking in shallow water. When available frogs are amongst the main food items, but fish are also taken. The rest of their diet is made up of invertebrates of various species. The size of individual food items is generally larger than those of Little Egret, being frequently up to 10 cm. Some old studies by Moltoni (1936) showed frogs (mainly Rana esculenta) to account for 40% of the birds diet in Italy with the rest comprising of Sunfish (Eupomtis gibbosus), Tench (Tinca tinca) and insects. Squacco Herons will feed at anytime of the day, but are most active at dawn and dusk, frequently feeding well after sunset. Grey Heron and Purple Heron Northern populations of Grey Herons are partially migratory although many birds winter as far north as Britain and the Netherlands. Most of the European population of Purple Herons is migratory with the majority of birds over wintering in Africa. A few Purple Herons may spend the winter in the extreme south of Europe (Voisin 1991). Grey Herons prefer to hunt in open landscapes and will utilize fresh, brackish and saline waters, in some areas even using the seashore. Although Grey Herons will fish along the edges of reedbeds they tend to avoid areas of dense vegetation. In winter especially Grey Herons will also hunt rodents in dry, open fields. The preferred nesting site is in tall trees with views of the surrounding
countryside. The marshes of the Tioxide site are almost certainly
only used for feeding. At present there does not appear to be any suitable
nesting habitat present. The Purple Heron’s preferred habitat is flooded lowlands with a strong preference for areas of extensive reedbeds. Permanent water is important, birds frequently deserting a nesting area if it dries out. Unlike Grey Herons Purple Herons are often found feeding in reedbeds and in the thick cover of rushes. Purple Herons nesting habitat also differs from Grey Herons, preferring large marshes with extensive reedbeds. It is possible that at least one pair of Purple Herons were nesting in the Padule di Scarlino in 1998. Purple Herons feed mainly on fish although reptiles, amphibians and invertebrates are also taken. Samples from a small number of birds in Italy showed that the main diet had been sunfish and insect larvae (Moltoni 1936). Quite large fish are frequently taken with prey up to 20 cm even being fed to their young. Throughout Europe there has been a steep decline in breeding Purple Herons for a number of years (Tucker et.al. 1994). A survey in Italy in 1981 (Fasola et al. 1981) estimated a total of 800-1000 breeding pairs, all of them north of Pisa. Tucker et al. (1994) reduced this estimate to 350-700 pairs. Notwithstanding the overall decline in population Purple Herons have either expanded their range into southern Italy in recent years, or Fasola neglected to cover the southern wetlands in his survey. A few pairs now breed at Lake Massaciuccoli immediately north of Pisa and between 3-8 pairs at Biscottino Pond just south of Pisa (Gustin 1994). Further south still Purple Heron occurs at the Orbetello reserve near Monte Argentario and in the Maremma Nature Park just south of Scarlino. The reedbeds on, and adjacent to, the Tioxide site are therefore an important link between small populations of Purple Herons both north and south along the coast of Tuscany. Little Bittern Ideal Little Bittern habitat is more or less permanently inundated with water, although the birds do not require the large expanses of unbroken reedbeds needed for the larger Bittern (Botaurus stellaris). Glutz von Bolzheim (1962) has positively correlated good Little Bittern habitat with good Great Reed Warbler habitat and the latter are common at Scarlino. Although only a single bird was seen in May 1998 the species is easily overlooked and it could well breed at Scarlino. As with the other herons, fish, amphibians and insects are their main diet with remarkably large fish (6-10 cm) being taken for such a relatively small bird. Early Italian studies again showed sunfish to be the major food item together with gudgeon (Gobio sp.), frogs and insects (Moltoni 1936). Little Bittern has been classed as “vulnerable” within
its European range, which is contracting, with reduced populations
in most areas. The Italian breeding population is estimated at about
1000-2000 pairs. It is thought that the main decline has been due to
losses on migration (European birds winter mainly in East Africa),
but, the pollution of wetlands and habitat loss have also been implicated
(Handcock & Kushlan 1984). Like other birds of prey Marsh Harriers suffered a steady decline in Europe from the beginning of the 20th century. Although data are rather incomplete it was estimated that between 80-100 pairs nested in Italy in 1945 falling to 25-35 pairs by 1975 (Chiavetta 1977). As in some other countries there was an apparent increase by the early 1980s, with up to 40-50 pairs in Italy by 1984 (Gemsbol 1989). No estimates have been found as to the current status of Marsh Harriers in Italy. As with most other birds of prey the fluctuation in numbers of Marsh Harriers have been attributed to direct persecution by man, habitat loss and especially between 1960-1980s, poisoning as a result of persistent pesticides. Overall the species might be increasing and it is not discussed by Tucker et al. (1994) as of special conservation concern. The habitat requirements both for breeding and hunting are extensive reedbeds, a habitat well represented around the Scarlino site. In the absence of more up to date information the possibility of up to three breeding Marsh Harriers on the Tioxide marshlands must be regarded as significant for the Italian population as a whole (possibly up to 6% of the national population). Marsh Harriers are legally protected in Tuscany, but as in every other area of Europe some birds are illegally killed. The Scarlino site represents a relatively safe haven for this small population. The presence of thriving populations of predators on industrial sites
is considered to be good biological indicators of healthy environments.
Many toxins bioaccumulate and the top predators are frequently the
first casualties of contaminated environments. Black-winged Stilts are very dependent on wet conditions (Dubois 1984), the preferred habitat being shallow fresh or brackish water with a clay, mud or sandy bed unencumbered with waterweed or stones. They like small islets and spits and readily accept man-made wetlands providing that there is ample biomass in the form of aquatic invertebrates. The birds feed alongside of herons and egrets with apparently little competition (see Figure 23). The birds nest on the ground usually in the open but sometimes in
very low vegetation. The nests are invariably near water often
on small
islets or mounds surrounded by water. With some habitat creation
and management it might be possible to induce Black-winged Stilt
to breed
on the Tioxide site. Between 20-30 Bee-eaters were present at Scarlino in May 1998. Birds were seen or heard at various times in many parts of the site ranging from the northern edge of the settling lagoons to the southern corner of the marshland. However, most of the birds were concentrated around the edge of the newly vegetated gypsum disposal site and the remnant wetland area to the south (Areas “A”, “C” and “D” Figure 21). At least 12 newly excavated nesting holes were found in the gypsum bank of Area “A”, and more may have been excavated later in the season. No previous reports have been found in the published literature of Bee-eaters nesting in gypsum waste from industrial processes, so these nests might prove to be the first recorded instance of such behaviour. It is not known whether Bee-eaters have nested in gypsum banks at Scarlino in previous years and, as yet, we have no information regarding their success rate. Bee-eaters spend the winter in Africa and return to Europe in spring.
An approximate timetable of Bee-eater activity on the Tioxide Scarlino
site is given in Figure
25. Protection of Bee-eaters on the Scarlino Site (i) The arrival and nest excavation of Bee-eaters at Scarlino should
be monitored over the next few years. The reasons for the decline in Skylarks are thought to be mainly agricultural practices that have changed cropping regimes. Especially damaging has been the change from spring to winter cereals and the more intensive management of grasslands (RSPB 1995). Skylarks build their nests on the ground in grassland, but if the sward is too long, the birds will not nest. The published range of suitable grass height is 20-50 cm (Dodds 1995). At least 20 singing Skylarks were recorded on the Scarlino site in May, mainly on the vegetated gypsum waste areas (Areas “A”, “B”, & “G”). It is important therefore that open, short grassland is maintained in some areas for these birds. Trees and shrubs should not be planted in every available area. Sheep grazing is an important part in preventing the grass from growing too long, but care must be taken to prevent over grazing. The published literature records Skylarks eating a wide range of invertebrate and vegetable food, differing with habitat and the age of the birds (Dodds 1995). Adult birds feed on a range of wildflower seeds, and in arable areas, on crop seeds that are an important winter food source. Invertebrate prey includes beetles, bugs, ants, sawflies and spiders. Young birds are fed almost exclusively on invertebrates. Studies on other industrial sites in the UK have shown that beetles, spiders and especially diptera formed a major part of the Skylark’s diet (Burton 1990). It is important that invertebrate food for Skylarks, and other birds, are maintained on the site. Consequently the use of pesticide sprays should only be used when absolutely necessary. Warblers Reedbed Warblers Great Reed Warbler (Acrocephalus arundinaceus) Reed Warbler (A. scirpaceus) On sites such as Scarlino where Great Reed Warblers are particularly numerous it is possible that competition from the larger birds encourages the smaller Reed Warbler to utilize the smaller, less robust reedbeds. During May 1998 no Reed Warblers were recorded in the main reedbeds of the Padule di Scarlino where Great Reed Warblers were particularly common. Elsewhere in Europe Reed Warblers have been observed to avoid Great Reed Warbler territories (Cramp et al. 1992). It is important therefore to maintain some smaller reedbeds, including those along ditches and the Pecora River, to provide uncontested nesting sites for Reed Warblers. If the only reedbeds on the site were those of the Padule di Scarlino then Reed Warbler populations could be vulnerable to competition from the much larger Great Reed Warbler. Moustached Warbler (A. melanopogon) Moustached Warblers are not dependent on new annual growth of plants to support their nests since they can use the broken stems of the previous season. This coupled with the fact that Moustached Warblers are resident in southern Europe (both the Reed and Great Reed Warbler are migratory, wintering in Africa) enables them to nest earlier than the other two species (Cramp et al. 1992). Although essentially a marshland species the Moustached Warbler is somewhat less dependent on flooded wetlands than either Reed or Great Reed Warbler. In various parts of its range Moustached Warbler favours slightly different habitats. In Armenia the birds in some areas prefer reed and sedge habitats whilst in others low bushes such as Tamarix are favoured. The edges of Phragmites reedbeds, often with sedges and Tamarix, are a frequent habitat in Jordan and in the Camargue they are typically found in Typha beds (Hoffman 1958). At Tioxide’s Scarlino site the Moustached Warbler has only been recorded from one locality (Area “D”) where, in May 1998, the birds inhabited mixed stands of Phragmites and Typha. Cetti’s Warbler (Cettia cetti) |
