Do oxpeckers provide overall benefit to giraffes?

Everyone knows that giraffes (Giraffa) and oxpeckers (Buphagus, https://en.wikipedia.org/wiki/Oxpecker) have an intimate relationship (e.g. see https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2019.0548 and https://koedoe.co.za/index.php/koedoe/article/view/637 and https://www.threatenedtaxa.org/index.php/JoTT/article/view/3055 and https://www.ajol.info/index.php/az/article/view/152924 and https://journals.co.za/doi/abs/10.10520/AJA03794369_3265 and https://www.researchgate.net/profile/Robert-Dowsett/publication/265632395_Oxpeckers_Buphagus_spp_on_game_animals_at_night/links/54b7e4b90cf28faced60bbfc/Oxpeckers-Buphagus-spp-on-game-animals-at-night.pdf and https://www.sciencedirect.com/science/article/abs/pii/0006320779900314 and https://journals.co.za/doi/abs/10.4102/koedoe.v57i1.1316).

However, how many realise that it remains unsure whether giraffes get any overall advantage from the relationship?

On the upside is that oxpeckers remove ticks and other ectoparasites (https://www.youtube.com/watch?v=1HS3Y36iK4M and https://www.youtube.com/watch?v=AxG6doDEnts). But on the downside is the risk of oxpeckers betraying the whereabouts of giraffes to potential predators.

Because it is difficult to weigh a chronic mitigation against an acute exacerbation, the net benefit for giraffes remains difficult to assess.

Oxpeckers utter various rattling vocalisations, in:

social communication within the species,
alarm vs their own predators, and
surrogate alarm on behalf of their megafaunal hosts.

Readers can hear examples in the following:
https://www.youtube.com/watch?v=dD6uS2UOCos
https://dibird.com/species/redbilled-oxpecker/
https://ebird.org/species/yeboxp1
https://www.pond5.com/sound-effects/item/59578813-rhino-bulls-walking-grass-riding-red-billed-oxpeckers-callin
https://search.macaulaylibrary.org/catalog?taxonCode=reboxp1&mediaType=a&sort=rating_rank_desc&
https://search.macaulaylibrary.org/catalog?taxonCode=yeboxp1&mediaType=a&sort=rating_rank_desc&q=Yellow-billed%20Oxpecker%20-%20Buphagus%20africanus

Oxpeckers sometimes behave (e.g. taking refuge behind the mane of giraffes) as if alarmed on their own behalf by the approach of potential predators such as the human species (e.g. see https://www.edwardselfephotosafaris.com/know-your-african-wildlife-oxpeckers). This is puzzling because the predators involved are extremely unlikely to target the birds in the first place. And it is not necessarily the case that oxpeckers, when on giraffes, simply maintain silence until giving the alarm on behalf of their hosts.

There is evidence that oxpeckers do aid the hook-lipped rhino (Diceros bicornis) by announcing the approach of humans (https://www.popsci.com/story/animals/rhino-oxpecker/ and http://researcharchive.vuw.ac.nz/handle/10063/3695). However, rhinos have exceptionally poor eyesight whereas giraffes have exceptionally good eyesight (https://journals.co.za/doi/abs/10.10520/EJC145788).

Giraffes have such extreme visual advantages that any augmentation of their vigilance by oxpeckers is questionable.

(As a thought-provoking digression, please see the sheer difference in the sizes of the eyeballs in https://www.inaturalist.org/observations/40127924. Nobody needs doubt that the eyesight of oxpeckers can be as good as that of giraffes, but is it not remarkable that this depend so little on size?)

Instead, the birds' calls - uttered for whichever reason - may possibly draw the attention of predators to individuals or small groups of giraffes otherwise fairly concealed by trees.

So, the problem resolves partly to an apparent conflict between two adaptive values:

that of the colouration of giraffes, which hypothetically camouflages them, and
that of their association with oxpeckers, which hypothetically undermines this camouflage.

This puzzle is unlikely to be solved soon, because relevant data are hard to collect and the behaviour of oxpeckers towards potential predators is complex and seemingly inconsistent.

In the meantime, I have gleaned the following information and illustrations from the Web, for the general interest of iNaturalists.

https://www.nationalgeographic.com/animals/article/animals-serengeti-tanzania-birds and https://blog.snapshotserengeti.org/2014/01/17/the-curious-case-of-the-giraffe-and-the-oxpecker/ and https://www.insidescience.org/news/these-birds-sleep-clinging-giraffes-groins

https://www.dailymail.co.uk/news/article-6055285/Oxpeckers-clean-teeth-giraffe-Tanzania.html and https://www.express.co.uk/news/nature/617305/Giraffe-bird-dentist-Red-billed-oxpecker and https://www.catersnews.com/stories/animals/giraffe-appears-to-chomp-on-bird-in-perfectly-timed-photos/

https://besgroup.org/2010/11/09/the-yellow-billed-oxpecker-and-the-giraffe/

https://www.travelnewsnamibia.com/news/stories/conservation/conservation-the-return-of-the-oxpecker/

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2028.1987.tb01115.x

BUPHAGUS ERYTHRORHYNCHUS

https://www.gettyimages.in/detail/photo/red-billed-oxpecker-on-giraffe-hluhluwe-umfolozi-royalty-free-image/107255149?adppopup=true

https://pixels.com/featured/giraffe-and-his-oxpecker-daryl-l-hunter.html

https://www.alamy.com/stock-photo-red-billed-oxpecker-buphagus-erythrorhynchus-two-oxpeckers-sitting-76080757.html

https://www.alamy.com/stock-image-red-billed-oxpecker-buphagus-erythrorhynchus-on-south-african-giraffe-165828514.html

https://www.alamy.com/stock-photo-red-billed-oxpecker-buphagus-erythrorhynchus-on-giraffe-giraffa-camelopardalis-125365173.html