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Sorry if this has already been discussed, but some observations on our feral Aesculapian snake population in London prompts my question. Several observers have noted that these snakes are frequently mobbed by birds such as blackbird and magpie, even when the snakes are on the ground, rather than climbing. On the other hand, I have never seen or heard of grass snakes or adders being mobbed by birds. So, firstly, am I right that only Aesculapians - being arboreal and therefore a threat to tree nesting birds - are mobbed by birds, and secondly, if so, is this a learned behaviour or do birds have some innate ability to recognise snakes which are likely to climb trees? Any opinions gratefully received, thanks! Will

I've seen similary behaviour with Hierophis viridiflavus next to Lyon (mobbed by magpie).

Not much to contribute, but I'd guess this is embedded in bird instinct to a certain degree, like this ...
https://www.jyu.fi/bioenv/en/divisions/ ... annespaper

thanks both; @Alexandre - since whipsnakes are often partly arboreal that makes sense as a response to viridiflavus. Was your snake in a tree/bush at the time or simply on the ground? @Jeroen - useful paper, thanks. I wonder if anything similar has been done for mobbing behaviour rather than predatory behaviour which is the subject of this paper?

Will Atkins wrote:@Jeroen - useful paper, thanks. I wonder if anything similar has been done for mobbing behaviour rather than predatory behaviour which is the subject of this paper?

A rather dull remark - the paper interprets it as predation, but how can you be 100% sure it is? Both phenomena will likely be detected by the same type of 'damage', no?

Springwatch this week showed a grassy predating a meadow pipit nest (on the ground). It ate one chick while the rest of the clutch escaped. When the snake returned to the nest there were shots of the parent birds, also joined by a stonechat, mobbing the snake whilst it was on the ground. I imagine that through natural selection tree-nesting species (weaver birds and Dispholidus/Dasypeltis spp. come to mind) will be more inclined to mob arboreal snakes, while ground-nesters will mob the terrestrial snakes more so, i.g. the species presenting the most danger to themselves and their chicks. I have not looked for scientific research to back up my points, they're just my (as yet untested) hypotheses. Food for thought anyhow...

Will Atkins wrote:thanks both; @Alexandre - since whipsnakes are often partly arboreal that makes sense as a response to viridiflavus. Was your snake in a tree/bush at the time or simply on the ground?

The snake was on the ground, on a trail, I was moving on bike when I saw it

Daniel Kane wrote:I imagine that through natural selection tree-nesting species (weaver birds and Dispholidus/Dasypeltis spp. come to mind) will be more inclined to mob arboreal snakes, while ground-nesters will mob the terrestrial snakes more so, i.g. the species presenting the most danger to themselves and their chicks.

Hmmm... I don't think natural selection makes certain bird species react rather to certain snake species - I think they'll hit any kind of snake that comes too close. The nesting site of the bird species and the habits of the snake species just make certain bird-snake clashes more likely.

@Jeroen - sorry for the dull reply! I assumed this study was to do with predation as the paper specifically looks at the zigzag pattern of vipers and whether this could serve an aposematic function, using the marks left by raptors (predators) on the model snakes as an indication of this. However I agree that the zigzag could also trigger mobbing behaviour in non-predatory species, for sure. Maybe a similar study has been done in which models of different species of snake (or at least types - long, thin vs stout, short etc) are placed in habitats and non-predatory bird species responses are directly observed? @Dan, thanks for this, I missed that episode of the BBC programme; I wonder if the mobbing was because a nestling had already been taken, rather than a pre-emptive behaviour? @Alexandre - again, thank you - so even though the snake was on the ground it was still perceived to be a potential threat by the magpie.

Will Atkins wrote:@Jeroen - sorry for the dull reply!

No, no, no ... I didn't mean to say your reply was dull, but the thing I wrote afterwards =>

the paper interprets it as predation, but how can you be 100% sure it is? Both phenomena will likely be detected by the same type of 'damage', no?