Foreign parts

One of the joys of foreign travel is discovering things that are different from one's own experience, whether they are new foods, social niceties, traffic signs or even plumbing. When one has an interest in a particular subject (such as the natural world), there is a special pleasure in finding things that are unusual, even though they may be commonplace where they are found.
During a week on the shores of Lake Garda, we found plenty that was new to us, but probably common in its own place. An example is the scarce swallowtail butterfly, which is only 'scarce' in its English name because it hardly ever turns up in Britain.

The normal swallowtail is hardly common in Britain, but is better known to us.
It seems that around every corner on the steep paths into the mountains there were new plants and insects, so there was much thumbing of field guides. A lovely orchid of hot woods is the violet limodore, a saprophyte without chlorophyll.
Sometimes you feel like a plant collector from the past, like Joseph Banks, when a 'new' species can't be found in the guide. I'll call this azzurropompom kingsdownii until I'm told what it is.
And this is a sub-species of house sparrow, passer domesticus italiae, with a brown head instead of the dusty grey cap of British version. Where is the line on the map where grey caps become brown? Presumably along the line of the alps?