\TrackLangProvidesResource{en-US}[2016/10/06 v1.2]

\providecommand*{\enUSanimals}{%
  \englishanimals
  \renewcommand*{\ladybirdname}{ladybug}%
}

\TrackLangRequireResourceOrDo{english}
{
  \TrackLangAddToCaptions{%
    \renewcommand*{\ladybirdname}{ladybird}%
  }
}
{
  \TrackLangAddToCaptions\enUSanimals
}