<fc #ff0000>WARNING</fc>: The following depictions have not yet had a chance to become canonical.
Yirha are any manner of benevolent spiritual creatures in any kavkem mythology based on Taaravahr (which is to say, all that are worth mentioning). While their exact nature varies, there is some common, shared imagery:
Kavkema assume birds were once intelligent (or still are, albeit in some unfathomable way). In some stories, they take the form of the trope of 'Ancients', forming a civilisation from before kavkema began to hold onto their history, or having a civilisation in another world parallel to the visible one (in Ne͡imakanaas̈ and Tkanala'ned).
Birds that are not aggressive to kavkema are generally simply referred to as itavesa (from ita (friend) and vesa (birds)). They are considered to be enlightened beings more often than not and thus frequently form the basis of kavkem decisions in which direction to next travel (vaguely analogous to augury in ancient Rome) - the birds are presumed to either be more knowledgeable about safe locations or, at the very least, better able to see which locations are safe.
Birds that are aggressive to kavkema (such as yerralejona) are not considered Yirha. They are either considered mere animals, perhaps devolved from their more enlightened kin, Tarnished (in Nitish Ynas) or otherwise corrupted from flying too close to Mekiva and its nexus of kiikama, or kiikama making a poor imitation of Yirha.
Vadukama are a counterpart to the Kaanakava, sharing their rough kavkem form but having benevolent intentions.
Nuture spirits (Ediemana, from ediem (one who caresses) and aman (care)) are friendly, selectively tangible and especially soft-feathered spirits that caress and snuggle lonely kavkema in the wild. Occasionally, they are known to taking a liking to the one or other kavkem, following them around. Their motivation is twofold: One is to experience the (physical) joy of companionship - the other is to nurture the resulting hatchlings, which they are extremely fond of.
It is latter trait that often lets kavkema exasperatedly consider Ediemana friendly pests, as they are known to make even principled kavkema stray from the philosophy of anti-natalism, as the Ediemana do not stop to consider the consequences of their obsessions. They unmistakably mean well, though, so they are classed as Yirha all the same - and the belief in their existence and the dreams of them have made many kavkem lives more bearable than they otherwise might have been.