Op deze foto's is er dus geen sprake van duidelijke snavelvlekjes. Op de ene helemaal niet en op de ander iets heel vaags wat gemakkelijk reflectie zou kunnen zijn.
Maar wel tweekleurige wang en lijkt een glanzende kop te hebben.
Cap colour and glossA frequent separation criterion appearing in the literature is cap gloss, with the cap of Marsh Tits being described as glossy black and that of Willow Tits as matt, dull or sooty-black or very deep brown (e.g. Perrins 1979,deep brown (e.g. Perrins 1979, Svensson et al. 1999, BWP).
Scott (1999) found that Willow Tits could also show a glossy black cap, however, while female Marsh Tits may also have dull caps with deep brown tones (Harrap & Quinn 1995). Examination of specimens showed considerable overlap of cap gloss, with 28% of Willow Tits showing slight or obvious gloss and 7% of Marsh Tits showing no gloss (fig. 1a).
Plumage gloss may vary considerably with viewing conditions and is of little use at distance. Lighting will have a significant bearing in photographs, as even a matt surface may reflect in strong light and a glossy surface will appear dull in deep shade (figs. 2a–b & 3a–d).
A further complication, mentioned in all sources, is that juvenile Marsh Tits have consistently dull black or deep brown caps (as do juvenile Willow Tits) and retain these until the end of the post-juvenile moult, in late September (figs. 2c–d). Cap gloss is therefore a highly unreliable characteristic, being difficult to assess in the field, open to misinterpretation in photographs, and variable in the hand.
Cheek areaThe majority of sources specify differences in the appearance of the pale cheek area of both species. Scott (1999) did not examine this character, although several authors agree on the principal differences (Harris et al. 1989; Harrap & Quinn 1995; Svensson et al. 1999; Gosler & Clement 2007; BWP).
The key distinction lies with the pattern of colouring on the ear-coverts and the sides of the neck, which together make up the pale cheek patch. On Marsh Tits, the earcoverts are a clean whitish colour that frequently contrasts with a pale, cold grey-brown wash on the side of the neck (fig. 1b). The transition between the white ear-coverts and greybrown neck is often quite distinct, following the curve of the ear-coverts themselves (figs. 2a & 3c). This results in many Marsh Tits appearing to have a much smaller white ‘face’ than Willow Tits.
The Willow Tit’s cheek is whitish or with a faint buff wash, but there is usually no abrupt colour transition behind the earcoverts (figs. 1b & 3d). Instead, Willow Tits frequently show a subtle colour gradient from the earcoverts to the sides of the neck, with an increasing warm buff suffusion. Where the cheek meets the mantle, the warm buff suffusion can contrast sharply with the grey-brown of the mantle (fig. 2b). In the field, the Willow Tit appears to have a larger, more uniform whitish cheek area in comparison with the ‘two-toned’ whitish and grey-brown cheek area of the Marsh Tit.
Examination of specimens revealed a moderately high degree of reliability for these differences, with 87% of Willow Tits assessed showing no distinct contrast in the cheek area and 94% of Marsh Tits showing a clear contrast between whitish ear-coverts and pale grey-brown neck sides (fig. 1b). No Marsh Tits displayed warm buff tones to the neck sides, while warm buff was present to some degree on 59% of Willow Tits.
Juveniles are more problematic, as both have wholly whitish cheeks and lack any grey-brown or buff on the neck (figs. 2c–d). Cheek pattern may nevertheless represent one of the better field characters for identification after the posjuvenile moult (i.e. from October onwards), with less overlap than for other plumage features. Particular caution must be exercised on worn adults or potential juveniles, and exposure of photographic images may also create difficulties by misrepresenting contrast or colour.
Richard K. Broughton
Separation of Willow Tit and Marsh Tit in Britain: a review British Birds 102, November 2009, 604–616
http://blx1.bto.org/pdf/ringmigration/24_2/broughton2.pdfLezen dat arikel allemaal want er staat nog veel meer nuttgs is en ik ga niet elke keer dat iemand iets zegt lappen tekst citeren.