THE LLOBREGAT DELTA by Ricard Gutiérrez
Only the most observant of birdwatchers will have noticed the coastal lagoons whilst coming into land at Barcelona's El Prat airport, perhaps on the way to other, better-known Mediterranean hotspots. This is an increasingly known birding place, possibly thanks to the internet and the different mega-rarities that have been found here (e.g. first Spanish Red-flanked Bluetail, Elegant Tern or Blue-cheeked Bee-eater). But the access to the area remains complicated due to the existance of large industrial and populated areas in the area.
Historically the problem has always been one of access. The Delta's invitingly flat lands lie only 15 kilometres away from Barcelona, and bird-watchers, faced with a succession of no-entry signs and high fences, jealously guarding the airport, golf courses, military bases, campsites and industrial estates, have opted to do their birding in areas with easier access. Thus, somewhat paradoxically, the presence of a large, expanding city nearby has tended to obscure rather than promote the faunistic riches of the Delta and there have always been very few local ornithologists able to extol its virtues.
The deltaic plain of the River Llobregat covers almost 100 square kilometres though today only about 600 hectares remain of the former extensive system of lagoons and marshes. The rest was swallowed up, first by agriculture and then, much more recently, submerged by industrial estates, campsites, the airport and the chaotic urban sprawl of modern Barcelona. A cross section shows a narrow sandy beach backed up by a relic dune system, fixed by stone pines (Pinus pinea) mainly planted at the turn of the century. Next comes the main wetland areas; reed-fringed, semi-saline, permanent lagoons mixed in with areas of Salicornia, other halophytic plants and rough grazing subject to periodic flooding. Separating the wetlands from the towns which ring the Delta, there is a zone of intensive market gardening. The actual river is highly polluted but there still remain two elongated lagoons - the Ricarda and the Remolar - in the southern section which form the basis of the two reserve areas which make up the Llobregat Delta Nature Reserve.
THE WILDLIFEOffshore, there is a constant movement of birds. Cory's, Balearic and Mediterranean shearwaters can be seen passing in droves in late summer along with 3 species of skua, gannets and cormorants. Gulls peak in winter, with 12,000 Mediterranean gulls in 1990/1991 and groups of up to 800 (normally up to 300-400) Audouin's gulls in spring amongst the commoner yellow-legged and a few little gulls. Sea duck can be vairably common in winter.
Erosion, provoked by the abusive construction of ports and breakwaters further up the coast and a series of reservoirs upstream on the river Llobregat, seriously threatens regenerative silt movement along the long, tideless sandy beaches. However, for the moment, an internationally important population of Kentish plovers (about 80-100 pairs) survives despite human pressure in summer. The beach is also a safe roosting place for thousands of gulls and a good place to observe passage waders and wheatears, black-eared included.
The strip of pines behind the beaches has suffered greatly from the construction of holiday home complexes and campsites, though in the best preserved sections at least nine species of orchid can be found. Breeding insectivores include the common Sardinian warbler, short-toed treecreeper and tits as well as being the area chosen by the great spotted cuckoo to parasite the local magpies. During migration the pines are further enlivened by Bonelli's, subalpine, melodious and other warblers and in winter, goldcrests, firecrests, robins, blackbirds, blackcaps and wrens arrive from further north.
The Remolar and Ricarda lagoons and the associated reed beds and marshes make up the main part of the Llobregat Delta Nature Reserve. Both are shallow and neither covers more than 10 hectares although they are surrounded by extensive reedbeds and the marshes. About 4000 duck overwinter. In winter groups of penduline tits and reed buntings from central Europe mix with moustached warblers from around the Mediterranean while white-spotted bluethroats arrive and add a touch of colour to the resident population of Cetti's and fan-tailed warblers. High densities of passerines in winter inevitably attract wintering diurnal raptors (over 60), predominantly marsh harriers, buzzards and kestrels, though merlins, hen harriers and peregrines are recorded each year.
The reeds are quieter in summer as few penduline tits stay to breed and breeding herons are variable with always internationally important numbers of little bittern (30),a few purple herons, up to four pairs of Grey Heron and depending on years, night and squacco herons (6 pairs in 2000) plus little and catle egrets. Apart from mallards, four pairs of red-crested pochard and one or two of pochards breed. Small numbers of nesting gadwall, shoveler and garganey breed irregularly. The basic summer population of the reeds and lagoons is completed by great reed and reed warblers, water rails, coots and moorhens with the first pair of Purple Gallinule breeding in 2001.
There is no clear limit between the reeds and the surrounding fields and in a few small areas, salt-loving Juncus, scrubby Salicornia and a few stunted reeds merge gradually into areas of rough grazing and abandoned fields. The water table is very high and these marshy areas are liable to retain large amounts of surface water in wet periods, providing a perfect temporary habitat for many birds. When rains or intentional flooding coincide with spring passage, over 500 waders, principally Tringa species, ruff and black-winged stilt fill the ten hectares of abandoned fields. Marsh sandpipers are annual visitors in April and red-throated pipits appear uncannily punctually around April 24th if there are sufficient wet fields. These same wet fields and marshes will also attract herons, ducks and terns, notably white-winged black terns and increasingly regularly, glossy ibises. However, the regular oversummering flock of Audouin's (up to 800) and Mediterranean (up to 150) gulls attract many colour-ring readers, as some of the gulls carry this kind of marks and are more or less easily read.
Breeding birds are more limited as the marshes tend to dry up in early summer, up to 250 pairs of black-winged stilts nest along with the fan-tailed warblers and Iberian wagtails. Lapwings and pratincoles used to nest . It remains to be seen if the Baillon's crake and little crake found breeding in 1983 and 1991 respectively, will return. In winter, the wet fields hold large populations of snipe, (e.g. 471 in 1992) along with a few jack snipe. Water and meadow pipits are common in wet areas and drier areas hold Dartford warblers and the resident crested larks.
In winter large numbers of birds including wagtails, finches, pipits, larks and chiffchaffs find refuge in and around the intensively used drier fields. Cattle egrets follow the flocks of sheep and the Delta is graced by large numbers of lapwings and golden plovers. In summer, corn buntings, short-toed larks, hirundines, swifts (alpine and pallid breed nearby), hoopoes and scops owl breed alongside the resident little and barn owls. Little ringed and Kentish plovers breed in the sandier fields but the Eleonora's falcons and hobbies seen annually, are only passing through. Spring and autumn migration also brings shrikes, bee-eaters, a few rollers, redstarts and Sylvia and Hippolais warblers to the few trees planted around the Delta.
MEDITERRANEAN GULLS IN THE LLOBREGAT DELTAMediterranean gull can be seen all year round in both the Llobregat delta and Barcelona's harbour. The area holds a large wintering population of some thousands and an important passage is noted in march and also from july onwards. Up to 150-200 birds (sometimes less) can remain in the area during the summer.
Behaviour of the birds change depending on the time of the year. During the winter, most of the birds remain offshore and are seldomly seen in the coast. Hence, colour-ring reading is very difficult, just in the part of the year when the species is more abundant. Casual observations, however, show that the percentage of ringed birds in this part of the year is very low, despite the presence of some adults marked with metal rings. This could be linked with the suposed origin of these wintering populations, the Black Sea, where colour-ringing is scarce. On the other hand, the oversummering populations have given better results, with birds coming from Hungary,Turkey and ocassionally the Netherlands but most of them from Italy being recorded.
WHERE TO WATCH GULLS
In the Llobregat delta, roosts are at sea in front of the shore. Some resting groups can be seen at the beach given there is no public around. During the rest of the years, they can appear at the flooded fields within the agricultural area or even at the marshes included in the Nature Reserves.
This delta is experiencing large transformations due to the works related to the deviation of the river 2,4 km south of its original bed (and land transformation around the current river mouth) as well as plans to enlarge the airport, with the construction of a 3rd runway. The best advice for visiting birders is going directly to Remolar-Filipines reserve, at C-31 motorway (former C-246, the Autovia de Castelldefels) where there is an information center where latest news can be obtained.
Best areas include :
1.- Beaches from Estany de la Murtra towards the river mouth (in winter, early in the morning or afternoon preferably week days for resting flocks)
2.- Remolar-Filipines marsh (information center)
3.- Flooded fields (if any) along Camí de València (check first the information center at Remolar-Filipines marsh for detailed information)
There is also a couple of websites with information on the area:
http://www.gencat.es/mediamb/rndelta [somewhat no longer updated (except for birdnews) but with plenty of information on the area, some in English]
http://www.parcsdecatalunya.net/deltallobregat.htm [with a modern version of the former but without much of its information. Contains however a very good downloadable pdf map of the area at http://www.parcsdecatalunya.net/dllob/llobr.pdf
Ricard Gutiérrez , Llobregat delta nature reserves .
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