Now they are moving from the north again. A chatty flock of tits in autumnal Germany could also contain Long-tailed Tits (Aegithalos caudatus) with a largely or even completely white head, which are often immediately counted as Aegithalos caudatus caudatus.
The Long-tailed Tit (Aegithalos caudatus) exhibits complex global variation, with 19 subspecies recognized. They can be divided into three groups: the caudate group in northern Europe and Asia. The europaeus group in southern and western Europe, northeast China and Japan. The alpinus group is restricted to the European Mediterranean and southwest Asia.
The caudatus subspecies of the Long-tailed Tit breeds in Fenno-Scandinavia, Eastern Europe, most of the former Soviet Union, parts of China and Japan, North and South Korea, and Mongolia. Since the corresponding parts of field guides appeared in European languages, this subspecies is located further west and south than previously stated. Long-tailed Tits are partial migrants and in some years occur invasively in large numbers in the Baltic countries and northwestern Europe.
Several subspecies of Long-tailed Tits occur in the southern and western parts of the caudatus subspecies area. These subspecies belong to the so-called alpinus/europaeus group. The distribution area of europaeus extends northwest to Benelux, Denmark, Germany, Poland and southern Sweden. Long-tailed tits of the subspecies Europaeus have been identified as migrants in Great Britain, Norway, Russia and Ukraine. Like the subspecies caudatus, the subspecies europaeus is a resident bird, although it can also migrate in harsh winters.
Unfortunately, a large part of the features of caudatus mentioned in the literature are also found in europaeus, especially in areas with many intermediate forms. In most identification books, the distinction between caudatus and europaeus is only considered in the text. Identification is made particularly difficult by the great variability of stripe-headed europaeus and the widespread occurrence of transitional forms. Individual white-headed Long-tailed Tits in a group of otherwise striped-headed birds usually – but not always – belong in this category.
Here is an attempt to summarize the most important distinguishing features:
Despite all limitations, the most important distinguishing feature is the head pattern: caudatus always shows a completely pure white head with a striking black button eye and a clear contrast to the sharply defined black neck band. In “white-headed” europaeus, remnants of the stripe pattern can often be seen. Even if this is the case, it might be very difficult to recognize. Sometimes these are just a few brownish feathers, especially behind the eye. The nuchal band in caudatus is always sharply defined and pure black, while in europaeus it is usually somewhat more diffusely separated from the white head. Caudatus never shows even the beginning of a pectoral ligament, as regularly occurs in europaeus. As soon as the attachment of a thoracic ligament is visible, the subspecies caudatus can be excluded. The underside coloration in caudatus is in most cases pure white than in europaeus and shows a pinkish tinge from the lower breast to the undertail coverts, which form the darkest area of the underside. In europaeus the underside is generally darker overall and shows some gray feathers, especially in the flank area.
In summary, it can be said that very clean and strikingly contrasting, pure white-headed Long-tailed Tits are always worth a second look, especially when they appear in groups of same-colored individuals. The high variability makes it essential that any determination of a caudatus candidate must be based on consideration of several individual characteristics. If not all subspecific characteristics are present, extreme europaeus or mixed forms cannot be ruled out.
Now the question is: Which birds really belong to the subspecies “caudatus”?
Long-tailed Tits of the subspecies caudatus must have the following characteristics:
- pure white, meaning “snow-white” head,
- sharp demarcation of the black neck from the white head,
- no chest band (not even close),
- white belly with flanks that are also white or only superficially pink,
- white or at least broad white banded tertials.
In view of the characteristics explained above, the Long-tailed Tits from the Großen Grabenniederung or the Pareyer Wiesen, Brandenburg/Germany were previously incorrectly referred to as Aegithalos caudatus, ssp. caudatus. In fact, the bird of the image above probably belongs to the subspecies europaeus with a clear caudatus-like appearance. One can see that the white-headed individual has no clear contrast between head and back and is also too “dirty” white on the underside.
In contrast, the blog image of Long-tailed Tits was ta
ken on Happy Island – an island in China’s Yellow Sea – and can be assigned to the subspecies caudatus, probably japonicus or more accurately sibiricus.
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