European Garden Spider, Araneus diadematus.

UC Berkeley professor Rosie Gillespie and her grad student Steve Lew identified my backyard spider as the European Garden Spider, Araneus diadematus. It is really common here in the Bay Area, and can be easily identified by the white cross on its back. These spiders aren’t especially numerous this year, although their numbers have increased over the past few decades. Initially from Europe, as their common name suggests, this spider appeared in the Puget Sound region in the 1970s. By the mid-90s, they were firmly established in the Bay Area. Araneus diadematus is an invasive species, an organism that is not native to the area and has a detrimental effect on the native organisms or ecosystem. And, there are quite a few invasive spider species in the Bay Area.

Another common invasive spider is Zygiella x-notata. They spin a very distinctive web—it looks as though a piece of the web is missing, as though someone has removed a single slice of pie. Other invasive spiders are actually displacing native spiders. For instance, the false widow, Steatoda grossa, is displacing the native black widow spider, Latrodectus hesperus. (This may not be such a bad thing, as the false widow’s bite, while venomous, is not nearly as harmful to humans as the real thing.) Another California spider, Theridion californicum, is being displaced by Enoplognatha ovata, which also hails from Europe. And, the native Funnel Weaver Spider, Hololena spp., may be facing some competition from the invasive Badumna longinqua, initially from Australia and New Zealand.

Certainly some of the spiders my friends and I are seeing are invasive. But, it is also the time of year when spiders build their webs. As my spider expert friend Joe Spagna put it, spiders “do the Charlotte’s Web thing” in the fall—the females spin a big web, make an eggcase, and then die. The baby spiders hatch in the spring. If you’ve been out and about over the past few weeks, you’ve no doubt noticed Halloween decorations all over the place. Along with vampires and mummies, you’ve surely seen a spider web or two. Joe brought up a really interesting question: “for a long time, I've wondered if the prominence of big, hairy orbweavers in Halloween folklore and imagery was actually a recognition of what was going on in nature this time of year.”

Joe and I spent some time digging through the some literature on Halloween folklore, but we didn’t find anything that specifically links Halloween spider imagery to the seasonality of spider web-weaving. Halloween folklore buffs out there, please comment if you know of any connection!

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What is on the public floors of the museum is just the tip of the iceberg of the Academy's collections. Over a span of more than 150 years, the Academy has built an invaluable collection that acts as a strong backbone for the museum. Twenty million research specimens and 38,000 live animals have to be carefully packed and transported. The Academy is undertaking the most massive move ever undertaken by a museum.

The Botany collection was the first to move out of Howard Street. It took only eleven and a half days to move two million specimens. For perspective, it took 61,300 cardboard inserts bundled with over 40 miles of twine to bundle the flora. Botany is only one of eight Academy research departments preparing to move.

The Academy's packing list is as varied as its research. Ornithology and Mammalogy have to transport Monarch, the last Grizzly bear of California. Because of its size and girth, it will not be boxed. However, it will take several movers to transport it carefully. Monarch will be joined by 30,000 other mammal specimens, including study pelts, skulls, skeletons, and the world's largest collection of marine mammal specimens.

It will be even more challenging to move the Academy's live animals. 38,000 live animals will be moved, water included, back to the Park in tanks of varying sizes. One of the aquarium's Australian Lungfish will be the oldest living animal to move. Over seventy years old, this fish has seen the Academy through many changes– a move to Howard Street, and now the move back to Golden Gate Park.

The Academy's Galápagos collection will also be packed up. It features thousands of Geospizine Finches (the group studied by Darwin) and the world's largest collection of reptiles from the Galápagos.

Cultural keepsakes will be preserved. Pre-Columbian Inca clothing, 12th Century Persian ceramics, fragile feather leis, full-sized Native Alaskan kayaks, 500 Japanese folk toys, and a renowned collection of eating utensils will also find their home in Golden Gate Park.

To give you a sense of the immensity of the project, 20 million specimens include the following:

• Over 200,000 fish specimens preserved in alcohol, including a rare coelacanth (thought to be extinct until discovered in the 1930s);
• 14.5 million insects and arachnids, including more than 874,789 flies, some 524,666 true bugs, nearly 3 million beetles, and more than 700,000 butterflies and moths;
• Nearly 100,000 bird specimens, including the now-extinct Guadalupe Storm Petrel and 10,600 sets of bird nests and eggs;
• More than a quarter of a million reptiles and amphibians from 166 countries.

The sheer volume of this move makes it a migration. Over 20 million specimens can not be moved in a day. It will take every one of those 265 days to move and prepare to share the wealth of the Academy once again with the public. To find out more about this "Great Migration" and the museum that will ultimately house the collections – visit http://www.calacademy.org/newacademy.

Cat Aboudara is the Special Projects Manager at California Academy of Sciences and works in the public programs division. The Academy is a wonderful fit for her because of her curiosity about the natural world and her experience in working with native California wildlife.

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