Studies of less familiar birds 165 Serin Viking Olsson

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1 Studies of less familiar birds 165 Serin Viking Olsson Photographs by R. G. Carlson and A. N. H. Peach Plates Compared with its well-known relative, the Canary Serinus canaria, of the Canary Islands, Azores and Madeira, the Serin S. serinus is smaller and not so brightly coloured. In many ways it bears more resemblance to the Siskin Carduelis spinus and this applies particularly to the females of the two species. Its small size, sober plumage and inconspicuous way of life mean that it is often overlooked in new localities. The Serin's steady spread to the north and east for at least 200 years indeed, for as long as we have written records is one of the more notable ornithological events. Its original range seems to have been confined to north-west Africa and southern Europe, from Iberia to the southern Balkans, where the species is found mostly in gardens and cultivated land with olives and cork oaks, but also in thick maquis in mountain areas. With his thorough survey of the spread up to 1925, Mayr (1926) supplied the background to the changes in the last 50 years. Fig. 1 shows some stages of the expansion. During its initial occupation of any new region, the Serin seems particular in selecting its habitat: hence colonisation has often been characterised by sudden appearances in good localities at advanced and isolated points, followed by a more gradual filling of intervening and presumably less attractive areas. Lowlands and river valleys have made the spread easier; open seas and highlands have slowed it down. The limits of a species expanding in this way are difficult to define and it is probably best to treat the edge of the range as a 'border zone' (cf. Kumerloeve 1956). The centre of this border zone in i960 as shown in fig. 1 is based on Creutz (1962) with small corrections in the west and extreme south-east and north-east (Olsson 1969b). For a decade or two up to that time the rate of expansion seemed to have slowed down: on the whole front from the French coast to the Baltic the advance was surprisingly moderate. Towards the end of the 1950's, however, and above all in the 1960's, the situation altered considerably. 213

2 214 Serin studies Fig.1. Some stages of the expansion of the range of the Serin Serinus serinus in Europe. Approximate positions of the northern and eastern limits of the breeding area in 1925 and 1960 are indicated by broken lines. During the 1960's the species pushed still further forward, and the line of dashes for 1970 takes in the most advanced breeding localities known up to and including that year in England, Denmark, Sweden and Finland. In the U.S.S.R. the line is based on rather incomplete data, especially in the southern part. In addition, all localities where the species has been reported one or more times in the western U.S.S.R., Finland, Sweden, Norway, Denmark, Britain and Ireland are marked individually Back in 1926 Mayr stressed the faster advance in the east than the west, and this tendency has prevailed, particularly in the north-east. Even down in Turkey, however, the spread is still going on and the Serin now probably breeds as far as the easternmost parts of that country (Kumerloeve 1966); accidentals have been found in the Caucasus and south-western Iran (Vaurie 1959). In Romania, too, the species has increased considerably lately (Radu 1960, Popescu 1965). On the other hand, it is difficult to get a clear picture of the present situation in the western parts of the U.S.S.R. There are detailed reports in the literature from better investigated areas, while vast intervening regions are not even mentioned, probably due to inadequate knowledge. Real advance to the east there seems to have been moderate during the last two decades, but the density in already occupied areas has greatly increased, as is typical of the consolidating stages. Zhezherin (1961) mentioned the Serin as a breeding bird in Bessarabia by the end of the 19th century; yet in the early 1950's the

3 Serin studies 215 Moldavian republic (which includes part of Bessarabia) was said to constitute its eastern limit at the Black Sea (Dementiev and Gladkov ) and the situation was still the same ten years later (Gladkov et al. 1964). A little further north, in the westernmost Ukraine, the Serin has also increased markedly. Talpos (1969) reported a density of about 50 per square kilometre in Mukachevo where it was rarely seen around Special investigations during by Zhezherin (1961) in the north-west Ukraine showed that it had become a 'not all too rare' breeding bird there; Rovno was mentioned as the easternmost locality. In 1948 and 1949, indeed, the species was found as far east as Kiev, and Zhezherin obtained indications of breeding there in 1959 and 1960, but these are still considered isolated occurrences (Gladkov et al. 1964). In a general survey of the recent situation in Litva (Lithuania), Ivanauskas (1961) wrote that 'one can meet the Serin in the whole republic', but that 'the occurrence east of Vilnius is very insignificant'. The first record in Belorussiya, east of Litva, was made as late as 1950 (Fedyushin and Dolbik 1967), but since then there have been quite a number of reports from different localities and in 1960 one was seen in Minsk, the easternmost in that part to date. Information from areas further north relates mainly to Estonia where the first record was in 1927 and, according to Mank (1970), 'the Serin has after that been found now and again, mainly in the vicinity of the towns of Tartu, Voru, Tallinn and Parnu'; ten to 16 pairs now breed in Parnu annually (Siigav 1969). Odintsova (1969) stated that the Serin had reached 'as far east as the Leningrad district' and further details were given by Noskov (1965, with additional data to 1970 in lift.). The first was found just south-west of Leningrad in i960 and the magnitude of the advance there is evident from the fact that about 50 have now been recorded, mostly in the southern suburbs, but also two to the north on the Karelian isthmus. The spring of 1964 was especially notable with nearly 20, the great majority males, but also some pairs and single females. The colonisation seems there to be definite, as Serins have also been recorded in November-January, and breeding may well have occurred already, although G. A. Noskov (in litt.) points out that no nests have yet been found further east than those in the vicinity of Narva, about 100 kilometres WSW of Leningrad, in The records in Denmark and Sweden before 1949 show that the initial influx there must have come from the German coast to the southwest. Several breeding records from the Danish islands and Skane (southernmost Sweden) date from those years. During the 1950's and 1960's, however, no real increase occurred in that area, but occurrences in eastern Sweden and Finland multiplied. A survey of the records in the last two decades throughout the whole Baltic area (Olsson 1969b)

4 216 Serin studies strongly indicated that this rapid increase in eastern Fenno-Scandia was derived from the pronounced, though less spectacular, advance south-east and east of the Baltic Sea. During Serins were found in Finland in six widely scattered localities and at one of these breeding was proved in 1967: not unexpectedly, this was on the southern coast of Finland at Espoo, just opposite Tallinn in Estonia. In 1968 Serins were found nesting in Linkoping about 300 kilometres to the north of earlier breeding places in Sweden (Olsson 1969a). The other records in Sweden have been summarised by Olsson (1969b) and these are all shown in fig. 1, together with a few new ones. In Fenno-Scandia the Serin has kept to lowlands, coastal plains and low islands, nowhere higher than 200 metres above sea level, except for an isolated record of a male at Kvikkjokk at 6j N in the mountains of Swedish Lapland on 30th June and 1st July 1964, which is also the northernmost known locality. In western Denmark the species has not made much progress since the 1930's. The 1940's brought a pronounced increase a little farther south in Schleswig-Holstein in north Germany, but not until 1961 was breeding proved in Jutland, just north of the border, and not one Serin has been found in northern Jutland since It is obvious that the spread in this part of Europe is proceeding very slowly. Similarly, it is clear from fig. 1 that, compared with the progress in the east and especially the north-east, the advance has been very slow towards the English Channel and the North Sea. By the mid-1950's, however, the species had reached much of the Dutch and Belgian coastline (Kumerloeve 1956), while along the French coast it was missing from little more than the outer parts of Brittany and Normandy (Kumerloeve 1957). This spread has, of course, influenced the situation in Britain. After the first record in Hampshire in 1852, the number gradually increased and even in those early stages there were occurrences in widely scattered parts of Britain and Ireland: during , for example, Serins were found as far west and north as Dublin, Edinburgh and Fair Isle. As already mentioned, such surprisingly distant records have also characterised the early stages of the advance elsewhere, as, for example, in Finland and Sweden. In broad outline, however, the expansion in Britain has taken place steadily from the south, with a clear dominance of observations in the southernmost counties and diminishing frequency to the north (see fig. 2). Up to the end of the 1940's the pattern was scattered and irregular. During the 1950's Serins were found almost annually, but usually in only one locality each year. Then there seems to have been a clear turning point about 1960, after which more and more were seen, as the following table of records (not individuals) shows:

5 Serin studies o In 1967 breeding was first proved in Dorset (Ferguson-Lees 1968 and in lift.). In 1969 at least three Serins were present in the same area and breeding was reported in another southern English county. Now that the obstacle of the Channel has been cleared and the species has gained a foothold in Britain, it seems likely that further breeding will take place in the immediate future and that in time the species will become firmly established here. Considering the great number of British and Irish records since the first in 1852 (87 to the end of 1966 and 141 to the end of 1970, involving at least 182 birds), it is strange that breeding was not proved until 115 years had passed. In Sweden and Finland, for example, the first breeding records were only the fourth and seventh observations of the species in those countries. The steady advance of the Serin from country to country defies adequate explanation other than that of a genetic change in migratory habits. Climatic factors have been suggested, but, if this were so, surely many other species would have reacted in the same way? Furthermore, the climatic range of the Serin today extends from mild, humid, maritime conditions in the west to dry, continental weather in the east, from the summer heat of north Africa and Asia Minor to the cold of Sweden and Finland. Equally, it seems impossible to show that sufficiently extensive and uniform habitat changes have taken place to the benefit of the Serin. On the other hand, the distribution of the records has given us clear information on the detailed mechanism of the spread. That northernmost observation in Swedish Lapland seems likely to have been a typical instance of prolonged migration or 'overshooting'.

6 218 Serin studies Fig. 2. Distribution of records (not individuals) of Serins Serinus serinus in Britain and Ireland from the first in 1852 to the end of Some adjacent localities in southern England have had to be combined because they are too close to be shown separately with these large symbols: hence the slight discrepancies between that map and fig. 1. The dominance in the south of the recent records during (filled circles) is well illustrated

7 Serin studies 219 The many records in south-east Sweden, and even the regular breeding at Ahus in eastern Skane, may have been due to abbreviated migration from the south-west to the Baltic States in spring. Post-juvenile dispersal in late summer has been proved on several occasions. Lastly, such records as one at Scalloway, Shetland, on 17th November 1968 were probably the result of drift. All these spreading mechanisms have played a part in the remarkable advance of the Serin through Europe. The distinct concentration along the southern coasts of Britain (fig. 2) shows that these have provided a landfall for birds coming from the south and south-east. The special significance of promontories is also interesting, while in only a few cases has the species penetrated far inland. I have mentioned that the Serin is exacting in its habitat preferences. Most reports from new localities come from towns, villages and other densely settled areas, particularly parks, gardens, churchyards, orchards and tree-lined avenues. Along the coasts of the Baltic States, however, there appear to be some remarkable exceptions: the species there is said to choose mostly light, dry pine forests on sandy soil. Serins seem to depend almost totally on seeds and buds taken on or near the ground in large open areas with abundant weeds (plate 34a). Harbours, railway yards and allotment gardens are often noted as feeding places. Because of this dependence, the birds regularly fly, alone or in small groups, between thickly wooded areas and open ground. The nest is usually well hidden in thick foliage, often in deciduous trees, but frequently in solitary evergreens among deciduous trees. The nest at Linkoping (plate 34) was in a Norway spruce Picea abies among rich broad-leaved vegetation. In England the first nest was in a western red cedar Thuja plicata in a suburban garden, and in Litva Ivanauskas (1961) also reported many nests in Thuja bushes and firs in gardens and parks, where deciduous trees and bushes must have been abundantly available. The nests on plates were in a garden area near Castelo de Vide, Portugal. The one on plates 29-3 ia was in a palm tree on a ledge formed where one of the large fronds had been cut back; the other on plates 3ib-33 was in a pollarded acacia. Many Serins were nesting in a plantation of these acacias, all at heights of about two metres. Dr R. G. Carlson (in litt. to I.J.F.-L.) noted that 'in these sites the nest was placed, in each case, fiat on a horizontal branch'. Nests in recently colonised parts of Europe vary from one to ten metres above the ground. For instance, of 24 German nests reported by Jung (1955), twelve were higher than four metres and four of those as high as eight or nine metres. A site far out on the branches is also very characteristic: of Jung's nests, 17 were built in the outer half of the branch and eleven of them in the outermost quarter.

8 220 Serin studies The nest in the acacia (plates 3ib-33) was the more characteristic, in both situation and construction, of the two photographed in Portugal. Well hidden from view by rich foliage (tied back for the photography), it was a little round cup similar in shape to the nests of Goldfinches Carduelis carduelis or Chaffinches Fringilla coelebs, but remarkably small with an interior diameter of only about five centimetres. The material used by Serins varies according to what happens to be available, but the framework is usually formed of dry grass or weeds and the interior lined with roots, lichens, seed down, feathers, horse hair and string; at the left-hand side of the palm tree nest was a tangle of cotton (especially plate 30b). Normally four eggs are laid, but clutches of three and five are not uncommon. The female alone incubates for some 13 days, being fed regularly by the male at intervals of about an hour. The male of the pair at Linkoping, Sweden, which were kept under regular observation, announced his arrival with brief 'chirr' notes at a distance of 20 to 30 metres, and the female would at once answer with an intensive, rapid, begging 'chi-chi-chi-chi...' until he reached the nest. Sometimes she left for a minute or two to defaecate, but returned at once to receive the regurgitated food which he passed to her in small portions over 15 to 20 seconds. Feeding was preceded by a ceremony typical of most finches, in which the female pressed hard on to the nest but raised her head and bill and vibrated her wings rapidly. Plate 29 shows a phase in this ceremony, but the male usually tries to get into a position in front of the female. With the two beside each other, the differences in the field between the sexes are very clear, but unfortunately they are difficult to see in black-and-white photographs. The male's bright yellow throat and breast are really striking and the conspicuous streaks on his flanks appear almost black against the yellow (plate 30b), though in fact they are brown. The cheek-patch of both male and female is distinctive, as also are the short, conical beak (plate 31b) and the notched tail (plate 33). The male sings mostly from twigs just beneath the tree tops. The song, somewhat similar to that of the Siskin Carduelis spinus, is a fast, hissing 'tsi-tsu-peripi-pi-tsi-tsu-tsi-tsu-peri-pi...' and so on, with variations. Near the nest at Linkoping one of his calls was like that of a Blue Tit Parus caeruleus: 'ti-ti-ti-chirr ti-ti-ti-chirr', or sometimes 'chiii, chi-chi-chi-chirr', the 'chirr' in both cases being sharp and distinct among the songs of all the other birds in the area. Between male and female one could hear a rather weak and short 'chuip' and a 'chitt-itt'. An alarm call directed at a dog was a high, piercing, repeatedly uttered 'tsiiii'. As nesting progressed, these Swedish Serins became much quieter and were soon so silent and retiring that it would have been difficult to

9 Serin studies 221 locate them at this stage, let alone find their nest. For many days after the young had hatched, the female hardly left them. The male passed all food to the female and, as soon as he had left, she regurgitated it to the young. This is beautifully illustrated at one of the Portuguese sites on plate 30a. The rim of the nest in that photograph is quite clean, as the female at first carefully eats all the droppings. When the chicks have reached an age of seven to nine days, however, the adults begin to leave the droppings (plate 32) which quickly accumulate (plate 33); by the time the young have left the nest, its rim and surrounding twigs are quite covered by faeces (plate 34b). At this stage it was possible to find the nest by searching for heaps of droppings on the ground beneath. When the young are small, feeding takes place at intervals of an hour or more, but as they grow this is gradually reduced to about 15 minutes. At an early age (as on plates 30a and 31a), it is possible after a feed to see an astonishingly large yellowish-green ball of food, as big as a hazelnut kernel, through the thin skin of each nestling's throat. During the last few days before they leave, the young seem to lead a dangerous life, fluttering and jumping around on the rim of the nest which by now is far too small for them. At Linkoping the female disappeared before the young flew and there the fledgling period was about 17 days; normally it seems to be about 13 days. Two broods are frequent. In late summer Serins gather in small flocks, usually foraging on open weedy ground. Axelsson (1965) mentioned areas of docks Rumex, ragwort Senecio and tansy Tanacetum as typical August haunts in southern Sweden. Ivanauskas (1961) reported that Thuja seeds seemed to be the favourite autumn food in Litva. Winters are severe in most of the recently colonised range and Serins migrate south and south-west from the northern countries, probably in the main to their original home in the western Mediterranean. According to Odintsova (1969), the species is now a regular, though rare, migrant along the point of Kursskaya (formerly Kurische Nehrung); and it passes Windenburg in mid October (Ivanauskas 1961). In the spring the first Serins arrive at Windenburg in mid April, which is about the peak time for migration of the species in Belgium and other parts of western Europe (Rappe and Herroelen 1966). In Scandinavia very few have been seen in April; the majority appear in May, mostly in the latter half. The monthly distribution of all records in Britain and Ireland is shown in fig. 3. Two peaks are clearly discernible. Serins are seen remarkably often in November and it seems that some attempt to winter in Britain. Numbers decrease to a minimum in March, suggesting that conditions are generally too hard in the latter part of the winter. There is then another marked peak in April and May when migrants reach British coasts from the south, followed by a sharp

10 222 Serin studies Fig. 3, Monthly totals of records (not individuals) of Serins Serinus serinus in Britain and Ireland from 1852 to Stippling is used for records to the end of 1960 and black for those during decline in June, July, August and September before another build-up in October. But surely this decrease in summer must reflect less effective observation rather than a real decline in numbers? These small birds become much more inconspicuous in the rich foliage of summer. Surely many must already be breeding in new localities in England as well as in little-known corners of Europe? ACKNOWLEDGEMENTS I am most grateful to Roger Gyllin for appreciable help with the translation of Russian literature, and also for many hints on papers on the recent spread of the Serin in the U.S.S.R. I have to thank G. A. Noskov for valuable information from the Leningrad area. I. J. Ferguson-Lees and P, F. Bonham revised the typescript and also produced a complete list of British and Irish records, from which Miss Karen Rayner drew figs. 2 and 3; the final form of much of the paper is largely a result of their work and I thank them for their time-consuming help. REFERENCES AXELSSON, P 'Nagot om gulhamplingens forekornst i Ahus, SkSne'.Faunaoch Flora, 60: CREOTZ, G 'Die Ausbreitung des Girlitz (Serinus canaria serinus L.)'. Falke, 9: DEMENTIEV, G. P., and GEADKOV, N. A Ptitsy Sovetskogo Soyuza [Birds of the Soviet Union], Moscow, vol 5: DYCK, J., JACOBSEN, J. R., KRAMSHBJ, E., and RAB0L, J. 1970, 'Rapport fra sjaeldenhedsudvalget med oversigt over godkendte forekomster '. Dansk Orn. Foren. Tidsskr,, 64: FERGUSON-LEES, I. J 'Serins breeding in southern England'. Brit. Birds, 61: FEDYUSHIN, A. V., and DOLBIK, M. S, Ptitsy Belorussii [Birds of Belorussiya]. Minsk. GLADKOV, N. A., DEMENTIEV, G. P., PTUSHENKO, E. S., and SUDILOVSKAYA, A. M Opredelitel Ptits SSSR [Key to the Birds of the U.S.S.R.]. Moscow, p 536. IVANAUSKAS, T. L 'Nove gnezdyastsesya vidy ptits v Litve* [Nesting birds new to Litva (Lithuania)]. Ekologiya i Migratsii Ptits Pribaltiki. pp

11 PLATE 29. Male Serin Serinus serinus feeding female on exposed nest on palm trunk, Portugal, June The fine streaks on her throat and breast are well shown; he has a yellow forehead, supercilium and breast. After a major spread in Europe this tiny finch appears to be colonising Britain (pages ) {photo: A. N. H. Peach)

12 P L A T E 30. Female Serin feeding newly hatched young at the same nest; note her dark cheek patch and light supercilium. At this stage she seldom leaves the chicks and then only for short intervals. Below, looking up at something overhead; this also shows a tangle of cotton on the left of the nest (page 220) {photos: A. N. H. Peach)

13 PLATE 31. Above, more general view of the exposed nest on a palm trunk {photo: A. N. H. Peach). Below, another Serin's nest in a more typical site on a horizontal acacia branch two metres above the ground and concealed by foliage, also Portugal, June 1968; note the species' short, conical bill (page 220) {photo: R. G. Carlson)

14 PLATE 32. Female Serin at the acacia nest with chicks a week old. She now leaves them for longer periods while she fetches food, often with the male. This nest was not only more typical in its site than that on plates , but also in its neat and compact structure. The material depends on what is locally available usually dry grass and weeds with a lining of rootlets, lichens, vegetable down, feathers and hair (page 220) {photo: R. G. Carlson)

15 PLATE 33- Another photo at the same site, depicting more clearly the position of the nest on a horizontal branch. The bright yellow rump (of both sexes) and the notched tail are well shown here. After the first week, as with most finches, the droppings of the young are left on the edge of the nest, usually on the side at which they arefed, and this accumulation is illustrated here by a comparison of these photos (page 221) {photo: R. G. Carlson)

16 PLATE 34. Serin habitat at Linkoping, Sweden (page 219). The nest was in one of the spruces left of centre; note the limes, beeches, maples and hazels to the right, and the weed area in front. Below, after the young had left, the tiny nest (coin diameter 26 mm) with accumulated faeces on one side {photos: Viking Olsson)

17 PLATE 35. Above, contour feathers of gulls Larus spp, Flintshire and Lancashire, July-August 1970, illustrating abnormal wear on the distal barbs. Below, part of Guillemot Una aalge, Co. Antrim, June 1970, showing abrasion and also fading of exposed wing feathers, particularly the primaries (page 236) {photos: G. Howsori)

18 PLATE 36. James Maxwell McConnell Fisher ( ) on 6th September 1970 at the XV International Ornithological Congress in the Netherlands {photo: Eric Hashing)

19 Serin studies 223 JUNG, K 'Zum Standort des Nestes beira Girlitz Serinus canarius serinus (L.)\ Beitr. Naturk. Niedersachs., 8: KUMERLOEVE, H 'Vom nordwestlichen Grenzraum der Girlitz-Verbreitung'. beitr. Vogelk., 5: 'Extension du Cini Serinus canaria (L.) [Serinus serinus (L.)] dans le Nord-Ouest de la France (Normandie-Bretagne)', Alauda, 25: 'Tendances expansives chez des especes de Carpodacus, Khodopechys et Serinus en Asie mineure'. Nos Oiseaux, 28: MANK, A. J 'Nove zaletne i nove gnezdove ptitsy Estonii'. Materialy Sedmoi Pribaltiiskoi Ornitolog. Konfer. vol 3: MAYR, E 'Die Ausbreitung des Girlitzes (S. canaria serinus L.)' J, Orn., 74: NOSKOV, G. A [On using decoy birds during ornithological field investigations (in Russian)]. Vest, Leningr. Gos. Univ., no. 3: ODINTSOVA, N.P 'Kolichestvenne sootnosheniya vidov semeistva v'yurkovych v. periody migratsii i Kotsevok'. Material)' Pyatoi Vsesoyuznoi Ornitolog. Konfer. Ashkhabad. OLDSSON, V. 1969a. 'GulhSmplingen (Serinus serinus) pa frammarsch i Sverige'. Fauna och Flora, 64: b. 'Die Expansion des Girlitzes (Serinus serinus) in Nordeuropa in den letzten Jahrzehnten'. Vogelwarte, 25: POPESCU, P. C 'New data on the distribution and nesting of the Serin (Serinus canaria serinus L.) in Rumania'. Trav. Mus. Hist. Nat. 'Gr. Antipa', 5: RADU, D. i960. 'Donnees recentes sur la nidification du Serin (Serinus canaria sermus (L.)) dans la Republique Populaire Roumaine' [French summary], Comun. Acad. Bucuregti, 10: RAPPE, A., and HERROELEN, P 'La migration de printemps et quelques donnees sur la reproduction des oiseaux en 1964'. Gerfaut, 56: SOGAV, P Haruldasi Unde Pdrnus. Eesti Loodus. TALPOS, V. S 'Izmeneniya v ornitofaune Zakarpatskoi nigmennosti v XX stoletii. Ornitologiya v SSSR, kniga vtoraya'. Materialy Pyatoi Vsesoyuznioi Ornitolog. "Konfer. Ashkhabad. VAURIE, C The Birds of the Palearctic Fauna. London, vol 1: 599. ZHEZHERIN, V. P 'Krassireniyu areala nekotorykh zapadnykh elementov ornitofauny Ukrainy'. Ekologiya i Migratsii Ptits Pribaltiki. pp Dr Viking Olsson, Sbdra Stordngsvagen 41, Finspang, Sweden