Across Spanish, French, (and many other languages no doubt) exist similar words in terms of spelling but which can have totally differing connotations and meanings; these are known as "false friends." So it is with certain names for bird species.
An amusing and embarrassing example was when the first Cliff Swallow turned up on St Mary's, Scilly in 1983.
A small group of Belgian birders were visiting the fabled isles for the first time, and within a few days during my first week there I had become drinking pals with two of them in particular in the evenings.
One of them, Gilbert, was ecstatic about the quality of the birding in general and the Cliff Swallow in particular, but added that the species had been recorded in Belgium in the past. I obviously raised my eyebrows somewhat in puzzlement but on such relatively short acquaintance was loath to suggest to him that he was talking tripe.

However, the next morning upon seeing me in the field, he rushed up to me apologising profusely and greatly embarrassed as well.
He had initially wrongly assumed the Cliff Swallow was Hirondelle des Rochers ("Crag Martin") on an approximately close translation; - hence his error as regards previous records in Belgium. Upon checking the literature he had realised that Cliff Swallow in French is named as "Hirondelle a Front Blanc" - literally "White-fronted Swallow" a true "mega" in European terms!
The Belgian lads were blown away by the stuff on Scilly that year, and at the end of their trip I asked if they would come back again. "Mais oui! - avec touts nos amis!!"

Happy Days!

Since I'm half-French, I had to learn both english and french names to get around in both countries, and one thing I noticed when I compared the two languages, was that French names are often closer to the scientific names of the birds, which often leads to names that are less "public-friendly".

One of the most obvious ones is the Wren. Its scientific names is Troglodytes troglodytes, which sort of means "cave-dweller", if my memory is correct. If I was in England and somebody asked me what is was, I would say a Wren, and though it may mean nothing to them, it is a short, simple name. In France however, I would say that it is a "Troglodyte mignon", which sounds really outlandish, for a bird which is one of the commonest in France ("mignon", by the way, is French for "cute"). A more compelling example is the Grasshopper Warbler, which gives a degree of familiarity with the English layman, but on the other side of the channel is unfortunately called "Locustelle tachetée", which would mean absolutely nothing to him.
Finally, once I went to twitch a Wallcreeper which wintered every year in the Paris region. Some other birders and I were looking up at the church facade which it was climbing, with telescopes and binoculars trailed at it. Some people on the street came over, interested to see what we were looking at. The name Wallcreeper is self explanatory, but the name "Tichodrome echelette" was met with blank stares.

Of course, this isn't always the case, and there are many good examples of more "user friendly" names, but sometimes I've got the feeling that maybe there would be more birders in France if some of the names weren't as outlandish or such a mouthful.

Thanks for the replies, very interesting. Someone else kindly sent a pm also pointing out the similarity to older English names for birds. With this in mind, a more accurate translation of the Bulgarian name for dipper is much more likely to be the same as the old English 'water ouzel' (though interestingly the Bulgarian name for ring ouzel translates as 'white throated thrush', and not ouzel/kos).

I'm guessing that much of the early classification/taxonomic work that put animals/birds/plants etc into categories / families, was carried out by English speakers, which would explain why other languages would have literal translations of these older names. I would also guess that variations of names will exist in some countries and regions that pre-date these classificatory systems. I'm sure though there are people on here who know much more about this.

One of the advantages of the old Peterson, Mountford and Hollom Guide to Britain and Europe was that it gave the common names in French, German, Dutch and Swedish. Through it I learned quite a few of the French names during the period when I regularly visited friends south of Angouleme. Of course it only helped if you were talking to a local who knew anything about birds - or a European birder who didn't want to practise his English

It's interesting that several of the Bulgarian names Chris quotes are similar to older English ones for the same birds. Windhover for Kestrel, Kinglet for the 'Crests, Water Ousel for Dipper.

Recently in Holland we came across the most confiding bittern I have ever seen. The bird gave brilliant views for about 15 minutes. A German birder came along & asked me what I had my scope on. Naturally I said 'It's a bittern.' Blank looks. Then my wife spoke more slowly -'I t 's a bit tern.' Still blank looks. Thankfully I had a guide book in my rucksack & the German guy's face lit up as he quoted the (now forgotten) German name of the bird. A quick reminder to me that the bird names we Brits take for granted often mean nothing to birders for whom English is not a first language.

I tried it in Arabic once but could only remember the name for a shrike and hoopoe.

When birding in France, I've found that using Latin names works best (assuming a lack of mutual understanding)

Recently I've been combining a renewed interest in birdwatching with trying to learn the Bulgarian language, and for those who want to learn another language I'd recommend this as a mutually beneficial exercise for improving both your language skills and understanding of birds.

I started off just trying to memorise bird names in Bulgarian, but it was only when I took the time to break down the names into colours, body parts, behaviours, habitats, bird families etc that the names were able to stick, and I was then able to learn other bird names much easier. I'm still very much a beginner, but there's a few examples I can share.

As you'd expect, bird names can't reliably be worked out via a literal translation from English. Blackbird for example, in Bulgarian, is Kos, whereas Dipper is Voden Kos (meaning, in Bulgarian, Water Blackbird - I think I prefer the English version). Swift (whether common or other) is almost the same, literally 'fast flyer', but Wren is 'Orehche', referring to its appearance, and meaning 'walnut'. The goldcrest translates as something like 'Yellow-headed little king' (or kinglet) and firecrest as 'Red-headed little king'. The Bulgarian name for Kestrel is Vetrushka, referring literally to its ability to hover on the wind.

I've never been particularly knowledgeable about bird families/taxonomies, but learning in another language seems to be helping with this. Yellowhammer in Bulgarian is Yellow Bunting (this may be obvious to most, but for novices the name is the primary clue). Dunnock in Bulgarian is literally 'grey-throated accentor'. There are a number of birds prefixed with 'Obiknovena' which means 'common', including (ironically given their current plight here) the turtle dove and the cuckoo (though I realise this prefix is technically there in English too). Sometimes the emphasis is somewhere else when the name describes the bird physically - so Redwing is 'White-eyebrowed Thrush'.

I'm sure there are many other, and better, examples that I haven't got to yet, but I'll enjoy learning. I have a great reference book in Bulgarian called 'Birds of the Balkan Peninsula' by Simeon Simeonov and Tanyo Michev, which I'm cross-referencing with english reference books (the latin names provide an invaluable link between both - ideally I'd remember those too, but unfortunately it's not happening at the moment).

Would be interested to know if others have tried birding in other languages...