2,    adults,    aves,    bird-nests,    birds,    boles,    breeding,    broods,    budgerigars,    budgies,    caves,    format,    holes,    laterally,    lovebirds,    nestles,    nests,    outdoors,    outside,    parakeets,    psittacines,    size,    trees,    trunks,    vertical,