called upon by the frightened cowherd boys
'Called by the terrified cowherd boys' — when Baka attacks, the friends run shouting Kṛṣṇa's name; their fear-driven cries are a form of bhakti and bring him immediately.
भीतगोपार्भकाहूतो बकचञ्चुविदारणः ।बकासुरारिर् गोपालो बालो बालाद्भुतावहः॥
bhītagopārbhakāhūto bakacañcuvidāraṇaḥ ·bakāsurārir gopālo bālo bālādbhutāvahaḥ
called upon by the frightened cowherd boys
'Called by the terrified cowherd boys' — when Baka attacks, the friends run shouting Kṛṣṇa's name; their fear-driven cries are a form of bhakti and bring him immediately.
who split apart Baka's beak
Kṛṣṇa rips Baka's beak apart; the demon's beak is split in half like a stalk of grass under the divine child's grip.
foe of Bakāsura
'Enemy of Baka' — the stork-demon Baka had come to kill the children; Kṛṣṇa's destruction of him is celebrated by the boys, who run home with the story.
the cowherd, guardian of the cows
The Harivaṃśa opens its Viṣṇuparva with Kṛṣṇa's childhood as 'Gopāla'—the cowherd child; the entire second parva is devoted to his cowherd līlās in the language distinct from the Bhāgavata's.
the boy
'The child' — the Bhāgavata's early chapters celebrate the paradox of the Infinite as the helpless bāla; this name is a meditational anchor for vātsalya-bhakti.
a mere child who wrought wonders
'Who as a child brings about wonder (adbhuta)' — every action of the child Kṛṣṇa is wondrous; the cowherds repeatedly express astonishment at the inexplicable deeds of this seemingly ordinary boy.