[vkou]

They are (deliberately?) juxtaposing calories (the scientific unit of energy) and kilo-calories (the nutritional unit of energy).

Unfortunately, the latter are, confusingly, also called called 'calories', despite one nutritional 'calorie' being 1000x of a 'regular' calorie.

[FunnyLookinHat]

I thought it was accurate - k-cal are usually represented as Calories (capital C) as opposed to the individual unit of measure: calories.

See: https://en.wikipedia.org/wiki/Calorie

[adrian_b]

Yes, that must be the source of confusion.

6000 to 12000 calories, not kilocalories, per day, means 1.5 g to 3 g per day of sugar, which is plausible for a humming bird.