Day 47 of 100 days of Blogging

How does moonlight affect birds? With all the Supermoon hoopla of late one can’t help but wonder! The last post mentioned the Swamp Sparrow apparently likes to sing in the moonlight, but he’s not the only one hanging out with the night owls. Here are10 facts from various studies about how birds are influenced by the lunar cycle.

#1. Eagle Owls use white throat feathers to communicate with each other, on nights with a full moon the feathers are more visible and communication behaviour increases.

#2. Northern Saw-whet owls are less active during moonlit nights in order to avoid ending up as potential prey for larger owls.

#3. Brau’s Petrels synchronize their journeys to an island mating ground with the full moon. Researchers note that these petrels are also more active in general during a full moon to take advantage of the light to feed.

#4. A Japanese study involving Streaked Shearwaters determined that this marine bird flies for longer periods and lands on water more often during nights with a full moon. However, researchers reported that sharks also take advantage of the increased light, so the shearwaters don’t remain on the water for long in order to avoid winding up as shark prey.

#5. During a full moon, the Whip-poor-will, a nocturnal insectivore, increases its activity levels, vocalizations and nest visiting behavior.

#6. Albatrosses are more active during a full moon.

#7. Researchers found that lunar cycles affect bird hormone levels. The daily variations in melatonin and cortcosterone disappear during full moons.

#8. Another study involving the white-browed sparrow-weaver found that males’ dawn songs started earlier when there was a full moon.

#9. A study involving Leach’s Storm petrels suggests that these birds assess predation risk. On nights with a full moon, the petrels remain on their nests to avoid nest predation from gulls that are also more active during a full moon.

#10. The Swallow-tailed Gull, a nocturnal seabird of the Galapagos islands, is most active during the new moon phase when its prey is closest to the water surface.