From what I can tell, this is intraspecies competition.
In Southern Africa, we have a situation whereby not all woodpecker species can peck the holes from start to end.
The ones who start the holes look similar to the ones in the article, but they are black, white and yellow with red flecks [1]. Then there is a smaller orange, white and black one that either steals the former's nest or uses an old hole, after which it proceeds to do some interior decoration and expansion. This rather fashionable bird is also the emblem of the University of Johannesburg. [2] [3]
There are some other woodpecker species, but these two are quite common in places where I have lived and although I am not an ethologist, I believe the comment about their interaction is accurate. The Crested Barbet is somewhat bigger than the Hoopoe, so it would be interesting to know the full picture behind their symbiosis.
I’ve always love seeing both of those birds in my garden. The barbet, with his squat sturdy frame and bright colours, especially.
I’ve never read about their interaction though, and neither of links that you’ve provided appear to explicitly connect the two species. All I know, and can find, is that they both like to nest in holes in trees. Do you have any info to backup this story?
I could find that the Bennet's Woodpecker does have the behaviour of re-using or stealing holes. On Wikipedia it's only very briefly mentioned, but the large Robertson's book may have something on it. [1]
Still looking for more information on what kind of holes the Hoopoe uses or makes; perhaps I was rather thinking of the Bennet's.
In Southern Africa, we have a situation whereby not all woodpecker species can peck the holes from start to end.
The ones who start the holes look similar to the ones in the article, but they are black, white and yellow with red flecks [1]. Then there is a smaller orange, white and black one that either steals the former's nest or uses an old hole, after which it proceeds to do some interior decoration and expansion. This rather fashionable bird is also the emblem of the University of Johannesburg. [2] [3]
There are some other woodpecker species, but these two are quite common in places where I have lived and although I am not an ethologist, I believe the comment about their interaction is accurate. The Crested Barbet is somewhat bigger than the Hoopoe, so it would be interesting to know the full picture behind their symbiosis.
[1] https://en.wikipedia.org/wiki/Crested_barbet [2] https://en.wikipedia.org/wiki/African_hoopoe [3] https://www.uj.ac.za/