The professional determination of bird species
Who is a serious birdwatcher, will not be satisfied with an inaccurate identification of species. Often enough it is just details, that distinguish one species from the other.
Experts, who professionally deal with determining of bird species and analyze their occurrence scientifically, are dependent on correct data sources. Christopher König administers the portal ornitho.de for the umbrella organization of the German Avifaunists. If bird notifications seem hardly plausible to him, he digs deeper. Once nine Red-backed Shrikes were notified already in April. The birdwatcher described the typical black blindfold around the eye. As Red-backed Shrikes are rather unusual at this time of the year Christopher König asked more questions. In the end the Red-backed Shrikes turned out to be Northern Wheatears. Another birdwatcher asked for reading out the ring of a Red Knot, which was on the photo clearly recognized as a colour labelled young Herring Gull.
Regarding to Christopher’s experience it is a challenge if one just knows the species from a field guide. This often results in funny mix-ups, which do not happen if one has observed the most important characteristics of species personally in all its details. His inquiries towards those, who registered the species, however nobody considers negatively. Usually people are grateful if they learn new details in the conversations and expand their knowledge by this. Crucial for ornitho.de is the accuracy. That is why only those birds may be registered that are determined without doubts.
Anyhow, even the most experienced birdwatcher make mistakes sometimes. There runs an automized validation of the system what is plausible at each time of the year. If someone registers a bird, he or she will be immediately be asked if he or she is really sure about it.
It is decisively to achieve a high comparability by reviewing the data.
If a rare species appears in one area the avifaunistic commission checks this regarding traceability and the actual status of science and technology.
Although Christopher himself usually counts on optical observations, he more and more with an increasing knowledge recognizes birds first by their calls and singing. For him the overall impression of a bird’s characteristics and the behavior is crucial. Based on his experience and this approach he recognizes bird species even in poor light conditions.
In Germany 400 regional coordinators and specialists for bird species support in verifying the data and in clarifying possible identification errors.
The challenging species and their detailed differences
In Europe the following examples of species pairs are recognized as typical traps for identification. On which slight difference you should focus is shown here. It is always about birds in their full coloration. Juvenile birds or birds in winter are infinitely more difficult to distinguish.
Grey-headed Woodpecker – Green Woodpecker
Lars Jonsson describes the color of the Green Woodpecker’s head as “robber mask” as the eyes are completely framed in black. The crown has a bright red color. Whereas the Grey-headed Woodpecker has just a little bit of red at the forehead and towards the eyes there is a thin black line. The Grey-headed Woodpecker is also a little bit smaller and slimmer than the Green Woodpecker. As the name says the Grey-headed Woodpecker is more grey at the belly and the head.
Common Ringed Plover – Little Ringed Plover
Common Ringed Plovers and Little Ringed Plovers we usually observe through a spotting scope from far away. The focus there is on head and legs. Common Ringed Plovers are a little more compact and brighter than Little Ringed Plovers, who have a more longish body, but usually they do not stand side by side to compare them directly. That is why this difference helps only partially. Most easy is to focus on their legs and the beak. While the Little Ringed Plover has a dark beak and more mud-colored legs, the beak basis and the legs of the Common Ringed Plover are yellow to orange. When flying a white wing band becomes apparent that the Little Ringed Plover does not show.
Spotted Woodpecker – Middle Spotted Woodpecker
The Middle Spotted Woodpecker is a little bit smaller than the Spotted Woodpecker and distinguishes mainly by its crown. This is completely red in the case of the Middle Spotted Woodpecker, also its jowl colors are not that distinct like in the case of the Spotted Woodpecker. The head of the Spotted Woodpecker is characterized by a mainly black and white marking – with just a little red part at the back of the head of the male. Also this is not always easy to say if the woodpecker sits far above in the tree and you just look up. From that perspective it is best to distinguish them by the underside. The Spotted Woodpecker has a much stronger red underside than the Middle Spotted Woodpecker. The red of the latter at the inner tail feathers is rather subtle and the white belly is a little black dotted.
Marsh Tit – Willow Tit
At a first glance the two species are hardly to distinguish. Besides their songs, which is more explosively in the case of the Marsh Tit and sounds more longspread in the case of the Willow Tit, there are only little characteristics to distinguish. Under the beak the Marsh Tit has a kind of a small, black bib, which is framed by the white of the head. The Willow Tit has a longer bib that reaches down to the throat. Also in the wings there is a white field to be recognized at the Willow Tit, which the Marsh Tit does not show.
Common Buzzard – Honey Buzzard
Although Honey Buzzard and Common Buzzard are not very closely related, they look very much alike. In addition, both species occur in different variants regarding the coloring. The best way to distinguish them are their structural characteristics at the throat. The Honey Buzzard’s throat is much longer and slimmer, and it stretches it forward. Comparing them directly one realizes also the longer tail feathers of the Honey Buzzard. A unique difference ist he beak. The one of the Honey Buzzard ends from the grey head and belly in a black top. The Common Buzzard’s ceres are yellow.
Common Chiffchaff – Willow Warbler
Both species are rather wide-spread in Europe and are often mixed-up. The Willow Warbler is slightly taller and glows stronger in yellow than the Common Chiffchaff. Also its supercilium is much stronger and more yellow, and the legs are brighter than in the case of the Common Chiffchaff. Those distinctive features are mainly valid in summer, in winter the differences are rather small.