Photograph of Bluebird, From <i>Bird-Lore, Vol. I, No. 2.</i>
<bdi><a href="https://www.wikidata.org/wiki/Q21515645" class="extiw" title="d:Q21515645"><span title="botanist (1880-1942)">Robert William Hegner</span></a>
</bdi>
<a rel="nofollow" class="external text" href="https://archive.org/details/birdlore12nati">The Internet Archive</a>