VOOUS KH (1948) A Dutch specimen of Anser arvensis serrirostris Swinhoe. LIMOSA 21 (1): 10-12.

Through the kindness of Mr. RoeIeveld (Utrecht) I had the opportunity to examine one skin and 27 prepared heads of Anser arvensis Brehm ("Rietgans"), caught during the severe winter 1946-47 near the southern coast of the IJsselmeer.
The skin is that of a juvenile bird of the year (Dec. 19th 1946 Barneveld, provo of Guelderland) with narrouw mantlefeathers and typically marbled grey undersurface. Its measurements are as follows (fig. 1) :
Wing 438 mm. Culmen 63.8; nail of upper mandible 17 mm. Greatest depth of lower mandible with shut bill 11,6 mm. (left hand side) ; 9 mm (right hand side): in the skin the right ramus of the lower mandible is somewhat forced in an unnatural position, thus making the measurements of the height on both sides somewhat inaccurate; its real measurement may be between 10 and 11 mm. Height of bill at base 34.6 mm. Number of teeth in upper mandible 22. The lower mandible is decidedly curved and there is only a rather narrow yellow band across the black bill. The quotient q (half the length of the culmen and height of bill at base; d. Limosa 18. 1946. p. 92) is 1.12. expressing a considerable height of the bill. From these it is quite dear that the specimen represents a tundra goose. of which measurements are given by D erne n tie f f (1936). Tougarinov (1941) and Johansen (1945). Dementieff; (serrirostris) 39 breeding birds (♂ ♀ ); wing 422-524; culmen 58.5-71.5; height of lower mandible 8-i2.5 mm. Tougarinov: (serrirostris) wing 428-520; culmen 58-71.5 ; height of lower mandible 8.7-13.3; height of bill 32.7-40 mm. J (j hansen: (ross:cus) wing 405-455; culmen 51-66; height of lower mandible 6.9-9.5; height of bill 30-33 mm; (serrirostris) wing up to 470 ; culmen up to 68 ; height of lower mandible 8-10.5 ; height of bill 34-35 mm.
While assuming that specimens of the western breeding populations of the tundra bean-goose (ross:cus) have generally smaller measurements than those east of the Taimyr Peninsula (serrirostris). showing a dinal variation. the above mentioned specimen represents a rather eastern migrant for which the 'name serrirostris must be used. especially on account of the high lower mandible. Anser arvensis serrirostris Swinhoe 1871 (China. wintering near Amoy) is new to the avifauna of the Netherlands. Its breeding range is situated in central North Siberia east of the Chatanga River and extending as far eastward as to where dinal variation makes necessary the separation of an even more heavily billed form mentalis (d. Limosa 18. 1945. p. 74-75).
A specimen which I think must be referred to rossicus. caught in the Netherlands (Jan. 18th 1888. Bunschoten) is mentioned by me in Limosa 17. 1944. p. 48. With one doubtful exception. this specimen was up to now the only Dutch beangoose known to me. which exactly agrees with the drawing given by J 0 han sen of a breeding specimen of rossicus. Similar specimens with almost identical bills are present in the series of prepared heads in the possession of Mr. Roe I e vel d. Like the above mentioned one. all are caught near Bunschoten (!). province of Utrecht. These specimens show the following measurements (hl = height of lower mandible; h = height of bill at base; q = quotient of half the length of the culmen and height of bill at base) : 1. culmen 56.4; hI 9.1 ; h 31.6 mm; q 1.12.
2. culmen 52.2; hI 9.8: h 30.0 mm; q 1.15.
3. culmen 56.7; hI 8.9; h 32.8 mm; q 1.15.
4. culmen 51.6; hI 8.2; h 295 mm; q 1.14.
N.B. In forest' bean-geese the quotient q is smaller than, or like 1; the lowest figure found in the remaining series of mainly forest geese being as low as 0.89, with a mean value of 0.99.
Besides, there is one rather heavy and long tundra goose-like bill, which following the measurements given by Johansen is either rossicus or serrirostris. Johansen mentions an intermediate rossicus-serrirostris breeding zone between the Taimyr Peninsula and the mouth of the Chatanga River.
5. culmen 61.4; hI = 10.9; h = 34.4 mm; q = 1.12. It is of interest to know that according to Mr. L. Blokhuis (Spakenburg) the distinctness of the race rossicus is very well known by the goose-hunters along the southern IJsselmeer-coast, who, moreover, distinguish the birds not only structurally, but also by their rather high pitched call.
When summarizing the above remarks, it has been. shown that during the severe winter 1946-47 a rather large number of tundra ,geese have been caught in the Netherlands, among which one specimen has been I refered to the race serrirostris with no more certainty than appears to be possible for a migrant. Tundra Bean Goose Anser serrirostris

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