Smallest owl

The elf owl (Micrathene whitneyi) from south-western USA and Mexico is usually quoted as the smallest owl averaging 12–14 cm (4.75–5.5 in) in length and weighing less than 50 g (1.75 oz).

Although the elf owl is most often quoted as the smallest, for some years there was another contender for the record – the least pygmy owl (Glaucidium minutissimum). More recently, the least pygmy owl has been regarded as marginally larger, with a weight of around 50 g (as opposed to 40 g for the elf owl) and a total length of around 15 cm (as opposed to a maximum of 14.5 cm for the elf owl).

The least pygmy owl was previously deemed to be as small as the elf owl because it contained certain small subspecies that have since been reclassified as not belonging to this species after all, some of which were as light as the elf owl, others of which were as short as the elf owl (but none of which were both).

The taxonomy of pygmy owls is currently very complicated, with different researchers holding different opinions as to their respective taxonomic status.

The elf owl typically nests in a hole made by another bird, or in cavities in trees. Sometimes, the woodpecker and the elf owl, may even nest in the same bush!