A yukkuri(s) is saying/doing something to attract the attention of humans or other yukkuris but nobody pays attention to them. Being social creatures, ignoring yukkuris can be a form of psychological abuse. This is especially true for koyukkuris who tend to desire attention.
Tag is used for both when they're intentionally ignored and when they're unintentionally ignored, as in the people they're trying to attract doesn't notice their presence.