This year they just didn't show up......
MIGRATION & SITE FIDELITY
DISTANCE: About 845km (525mi) non-stop across the Gulf of Mexico, and then up to another 1,600km (1,000mi) into Central America; RTHU that nest in Canada must also fly from there to the Gulf Coast, a distance of another 1,600km (1,000mi) or so.
ELAPSED TIME: Estimated 20 hours to fly across the Gulf of Mexico. (Some RTHUs may go overland through Mexico.)
FEEDING & METABOLISM
RATE: Eats about its weight in nectar or sugar water each day.
FREQUENCY: About 5-10 times per hour for 30-60 seconds each time
BODY TEMPERATURE: 40.5 degrees C (105-108 degrees F)
TORPOR: On cold nights, a RTHU can lower its body temperature by about 20 degrees C (30 degrees F), thus conserving energy that we be used to maintain its normal temperature. The next morning, the RTHU speeds up its metabolism and get its body temperature back up to normal within a few minutes.
ENERGY USE: On a typical day, a RTHU needs about 10 calories of food to survive. This can come in the form of carbohydrates (sugar water or flower nectar) or fats and proteins (primarily from tiny insects and spiders).
Fascinating aren't they?