Ladybug clusters on long tree branches resemble some red berries or tiny flowers, and when they cover the entire area of a tree trunk, it is even more confusing. Such an amusing sight may be seen during ladybug migrations from cold to warm wintering sites, and then in reverse.
This natural phenomenon may be seen in various corners of the planet, and its variable route is hardly predictable as well as the season itself, so ladybug invasions mostly catch everyone by surprise. One of the most bewildering ladybug invasions happened in 2009 when tonnes of beetles surprised a town in Colorado with a spontaneous massive visit. The entire neighbourhood teemed with ladybugs.
This may occasionally happen here and there, but there is one approved site where they are observed annually in late November. This is Muir Woods National Park in California, less than 20 km from San Francisco. They love hanging out around the crossroads of Prince Trail and Stream Trail. But be careful not to stamp on a bundle—they are everywhere in the grass. Another great spot to watch the hibernating ladybugs is the Redwood Regional Park.
The ladybugs 'winter gathering' around San Francisco usually lasts from November when they arrive until February when they slowly leave. The best time to spot the red trunks is still November, as later on ladybugs hibernate in trunk holes. They will come out again in sping to mate and soon leave for home.
An interesting fact is they will never come back again, for they live only one year, but the next generation will find the spot, and huge ladybug congress will happen again. Scientists don't know for sure, but it's supposed the beetles follow feromone tracks left by previous generations.