Magellanic Woodpecker - BAM-Bam!

In this segment from his 1998 series, The Life of Birds, David Attenborough summons a male Magellanic Woodpecker by mimicking it's signature double knock on a tree in Patagonia.  In addition to this clip, the BBC maintains an entire page of information on the Magellanic Woodpecker here at this link.  Notes that accompany the Intro clip on that page describe different foraging behavior of females and males when raising nestlings to strategically maximize food resources.  Males have been known to catch lizards and even the chicks of other birds!

Campephilus double knocks vary in volume and are not necessarily always loud.  But, consider the loud double knock of the Magellanic Woodpecker that occurs at 1:33 min into this clip.  The power behind that double knock is illustrative, I think, of how very loud the double knocks of its northern relative, the Ivory-billed Woodpecker, could be, as often described in historical literature, given its substantially larger dimensions.  BAM-Bam!

Ivory-billed Woodpecker
- length 48-53cm/19-21in (approximate)
- 450 - 570 grams (approximate)

Magellanic Woodpecker
- length 36-38cm/14-15in
- male 312-363 grams; female 276 - 312 grams

Source for measurements

- Woodpeckers: A Guide to the Woodpeckers of the World by H. Winkler, D. A. Christie & D. Nurney