Rainbow lorikeets feed on both seeds, which they crack with their beaks, and on nectar which they collect on their brush-like tongues (hence trichoglossus), though they prefer nectar.
To indicate the desire to be fed nectar rather than seeds, some birds will maintain eye-contact with the human feeder, open their beaks, and extend their tongues to their full length.
That is to say, this expression of the instrumental microfunction ('I want it') differentiates the desired object by the bodily action used to process it.
ChatGPT comments:
That’s a brilliant example of embodied semiosis—using the instrument of consumption (the tongue) as an iconic representation of what they want. It’s reminiscent of how some primates will mimic an action to indicate a desired result, like a chimp extending an open hand to request food.
What’s particularly striking is the eye contact. This suggests that the communication isn’t just about the physical act but also about securing attention and ensuring the signal is received and interpreted correctly—something that goes beyond simple stimulus-response behaviour.