I just returned from Antarctica where we made many shore excursions and spent a great deal of time among penguins - mainly Gentoo, and some Chinstrap species.
They were fascinating and there were several distinct behavioral patterns that I observed but did not understand. I'm not really asking for explanations here, but just a good introductory source of penguin behaviours. When I've searched online everything I've seen is either too general and basic to be helpful, or too technical and specialised for me. I have a strong general science background and I'm an AAAS member and I have one ethology course from decades ago, but reading peer-reviewed research papers on this would be over my head. We were there in March (late summer) so the juveniles were adult-sized but still had juvenile plumage.
(Gentoo) being on beach or snowfield where there was a dense, mainly uniform distribution of adult and juveniles standing or laying around, when in the midst of this a line (typically 4-8) of adults would walk briskly, single file, through the groups of standing individuals, and even through the groups of standing humans, all looking straight ahead and apparently with a sense of purpose. They would walk out of sight. Why, and are they connected or related somehow?
(Gentoo) coming up to us and grabbing anything loose like backpack straps, number tags on lifevests, or pantlegs flapping in the wind and pulling. This was not pecking like they would trying to get an adult to feed them, but I mostly saw this with juveniles. We were under instructions to not make any noise or motion that would alter their behavior but when one started tugging on my lifevest inflation tab I had to yell to stop him. (IAATO guidelines are to stay 5m away from wildlife but the penguins didn't attend our orientation seminar and anytime we stood still they came up to us) Juveniles frequently nestled between our legs if we stood still (all of us were wearing thick, insulated, multi-layers of pants), but this is easy to explain regarding chicks nestling in the adult's brood pouch, since we frequently saw adult-sized juveniles exhibiting other chick behaviours, eg, food-seeking from adults.
(Chinstrap) large groups (30-50) of individuals standing tightly together when many (but not all) would suddenly point their heads up and start to vocalise, sometimes flapping their wings. This would go on for a minute or so and then stop suddenly. I made videos of this. I never saw any sign of a threat, say from a skua or seal, nor did they seem to be looking at anything, and nothing obviously changed that made them stop.