Barn swallows have forked tails. This fledgling begs for food.

When warm weather brings insects, the swallows aren’t far behind.

There are eight species of these insectivores in Colorado: Six are regulars in Denver from April to late September, and the other two are rare.

A visit to Bluff Lake Nature Center in late April netted all six regulars: barn, cliff, violet-green, tree, northern rough-winged, and bank. The rare ones are cave swallow and purple martin.

1. Cliff swallows have whitish forehead patches. 2. The most colorful swallow is the violet-green swallow. 3. Tree swallows boast dark blue iridescent heads and wings. 4. The bank swallow has a band on its chest.

The rapid, chaotic flight of a barn swallow can make one dizzy trying to follow its flight path. But its unique forked tail gives its identity away. The cliff swallow has a distinctive whitish forehead patch. The violet-green swallow is the most colorful, and its name says it all. Tree swallows have iridescent dark blue heads and wings in sharp contrast with their white throat and belly. The northern rough-winged and bank swallows are smaller and mostly brown with white undersides. A dark band across its upper chest distinguishes the bank from the northern rough-winged.

Bird Walks: June 6 and July 4. Two start times: 7:30am and 8am. Walks are free, but you must RSVP at blufflake.org/birdwatching. All are welcome. Bring your own binoculars or borrow a pair from your guide. 11255 MLK Jr. Blvd.