Colombian police help carry people's household belongings across the Tachira River from Venezuela, top, to Colombia, on the border that separates San Antonio del Tachira, Venezuela from Villa del Rosario, Colombia, Tuesday, August 25, 2015, during a mass exodus of Colombians. Venezuelan President Nicolas Maduro vowed to extend a crackdown on illegal migrants from neighboring Colombia he blames for rampant crime and widespread shortages, while authorities across the border struggled to attend to droves of returning deportees. (Photo by Eliecer Mantilla/AP Photo)

A bird is cleaned at the International Bird Rescue in Fairfield, California January 20, 2015. A gooey, unknown material discovered on the eastern shores of San Francisco Bay is clinging to the feathers of birds, and more than 100 birds, mostly species of oceangoing, diving ducks, have died after their feathers were fouled by the viscous substance now undergoing testing at state labs in Sacramento. (Photo by Robert Galbraith/Reuters)

In this Thursday, January 29, 2015 photo, the backseat of a rented 1957 Buick is packed to the brim with flowers, to be transported to Havana from San Antonio de los Banos, Cuba. Every Monday and Thursday morning, self-employed flower vendor Yaima Gonzalez Matos leaves her home to visit a dozen farmers who sell her sunflowers, roses, lilies and other blooms. She loads the flowers into the rented American classic and delivers to customers in the capital. (Photo by Ramon Espinosa/AP Photo)

Participants wearing superhero costumes attend the World DC Comics Super Heroes event in San Martin de Valdeiglesias, near Madrid, April 18, 2015. To celebrate the anniversary of the publication of the very first Superman story, DC Comics are asking fans to help set a new world record for the largest global gathering of people dressed as DC Comics Super Heroes. (Photo by Andrea Comas/Reuters)

An injured person reacts during a protest against the new government of President Manuel Merino, in San Martin de Lima square, in Lima, Peru, 14 November 2020. Merino took office on 10 November amid a controversial constitutional process after the dismissal of former President Martin Vizcarra for “moral incapacity” by Peruvian Congress. (Photo by Aldair Mejia/EPA/EFE)

Indigenous Q'eqchi girls practice taekwondo with their teacher, Danny Coy, on a dirt court in the middle of the village in Tipulcan village, San Pedro Carcha, Guatemala, on 25 November 2019 (issued 27 November 2019). Tipulcan village girls learn taekwondo to combat sexist violence and harassment they have suffered in their community in northern Guatemala. (Photo by Esteban Biba/EPA/EFE)

Mailin Gobbo reacts as she leaves the courtroom after hearing a judge acquit former Catholic Priest Carlos Eduardo Jose, who she says sexually abused her for years when she was an adolescent, in San Martin, Argentina, Tuesday, March 9, 2021. The court acquitted the 62-year-old, citing the statute of limitations had run out. (Photo by Natacha Pisarenko/AP Photo)

Sharon Beals is a San Francisco based photographer who has photographed nest and eggs specimens collected over the last two centuries at The California Academy of Sciences, The Museum of Vertebrate Zoology, and The Western Foundation of Vertebrate Zoology. While few nests are collected today, these nests and eggs are used for research, providing important information about their builder’s habitats, DNA, diseases and other survival issues.