Apologies for leapfrogging back over the French connection, but just to wrap up my involvement here--
FIRST: '(7) Cocker spaniels are one of the most popular pet dogs' (and I opt, on second thought, for lower case for the breed) -- I did not think twice about 'spaniels are one of', and I suppose it has to do with notional concord and natural language use, Hela.
Using the singular ('the cocker spaniel') is a more formal form: '
The Cocker Spaniel is the smallest member of the Sporting Group. He has a sturdy, compact body and a cleanly chiseled and refined head, with the overall dog in complete balance and of ideal size.' The singular is more comfortably used in this kind of statement-- and notice the capitalization (this sentence is from a breeder's website).
For general conversation, however, we tend I think to use the plurals: 'I like cats (not 'the cat')'; 'cats are selfish pets' (not 'the cat is a selfish pet'). Therefore, my naturalizing brain automatically chose the plural form. There are many kinds of dogs-- cocker spaniels, golden retrievers, border collies-- and one kind is cocker spaniels. I'm sure that you can see where this leads, Hela-- there was an immediate lack of concord between 'spaniels' and 'is', so I changed to 'are'; and then, notionally, my mind supplied 'one kind/sort of... pet dogs' and all seemed well with the revised sentence.
I may be in trouble with the stricter moderators for this, unless Casi can come up with a better rationale than mine for this phenomenon.
SECOND: Yes, I am aware of the House Sparrow and Starling problem there, MrP. I sometimes visit
BIRD FORUMS for information on birds (scroll down slightly for House Sparrow/Starling talk).