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Friday, April 29, 2011

Bushtits Move In

New Neighbors

A pair of Bushtits, Psaltriparus minimus, just built their nest in the live oak tree behind the Butterfly Pavilion. Kimball Garrett, our resident bird expert, found the nest this Monday and promptly sent me an e-mail detailing the nest's location. As soon as I got into work on Tuesday morning, I headed out to the Butterfly Pavilion to check it out.

Adult Bushtit, Psaltriparus minimus

Nest Hunt

Thankfully Kimball had given clear instructions to find the nest, as it was very well hidden in the oak foliage. The effort was well worth it, as it was one of the coolest nests I've ever seen in the wild. As the picture below shows their nests are woven from dry plant material and hang from branches of the tree. They are small and dainty, this one measures about seven inches from top to bottom. The small opening at the top of the nest, which is only about an inch in diameter, is just big enough for the adults to enter and exit.  

Bushtit entering nest

Bushtit Behavior

After spending a good portion of my morning watching the nest, I realized I had to blog about it. But what is a blog without images, or even better some actual video footage. I ran up to my colleague, Sam Easterson's office to see if he could get some for me. Sam recorded the nest for about an hour, and we captured some interesting behaviors, including removal of fecal sacs! A fecal sac is clean, tough membrane that encloses the excrement of young birds. Not all birds produce fecal sacs, but for those that do sacs are usually produced directly after each feeding and promplty removed by the adult to maintain a clean nest interior. 


video

Bushtit cleaning nest

Sam Easterson is a video naturalist and also our new Media Producer for the North Campus and Nature Lab exhibits. He's really into implanting cameras into natural environments, and is best known for his animal borne imaging work.

Friday, April 22, 2011

North Campus Insect Survey

Survey Fun


As mentioned in an earlier post New Fly for North Campus, we've been trapping insects on the North Campus for a while now. This week however, is a milestone for NHM as we held our first quarterly insect survey. Our aim was to go after the insects that our Malaise trap wasn't sampling, like large flying insects such as crane flies and bumble bees and ground dwelling insects like earwigs and beetles.  Since this was our first time and the site is still an active construction zone, we limited participation to NHM staff and partners. As the specimens get prepared and sorted, I'll keep you all up to date on the species we identify.

Brent "the bug guy" Karner demonstrates proper use of a
beating sheet to our USC partners.

Brian Brown showing off his aspirator (aka pooter) skills.
Look closely, I swear there's an insect there!

A common insect, but nonetheless an impressive catch.
Female carpenter bee in the genus Xylocopa

Special thanks to Cordell Corporation for allowing us to access the site.

North Campus Pill Bugs

Finding Pill Bugs

I always knew we'd find pill bugs in the North Campus, but until recently I didn't know what species, or that they'd have such an interesting story.

In the North Campus there are two species of terrestrial isopods, what we at the Museum call pill bugs and their relatives. The Common Pill Bug (aka roly poly), Armadillidium vulgare, rolls up into a tight little ball when disturbed. We also find a closely related species, the Common Rough Woodlouse, Porcellio scaber, a more agile creature. In North America most of the people I've talked to refer to both as pill bugs, whereas in England, where I grew up, we called them all woodlice! Regardless of what one calls them, they both share a similar story of how they come to live in North America.

Common Pill Bug, Armadillidium vulgare

Common Rough Woodlouse, Porcellio scaber

An Introduction

Both the Common Pill Bug and the Common Rough Woodlouse are originally from Southern Europe and Northern Africa. Before Europeans arrived on this continent neither of them lived here. Both species are associates of plants, living in soil and leaf litter and have hitched rides from Europe to the U.S. with a little help from us. One possible explanation is the imporation of plants and associated soil, that began steadily streaming into ports-of-call as the continent was settled. A more interesting, and might I say apocryphal story, unfolds if we look to the high seas.



Image courtesy of the Library of Congress
Two if by Sea

In the days of wayfaring seamen and wooden ships, soil and boulders were used as ballast, to ensure a properly balanced vessel. This earthen ballast would be discarded when it was time to fill the holds with precious cargo and booty. It is not so much of a stretch to think that in some instances surviving creatures, eggs, seeds, and more managed to colonize the shores of these new lands. Whatever the mode of their introduction, it is clear that they were introduced more than once and in multiple locations. Today these creatures are widespread throughout the world and are a very common site in L.A.'s parks, backyards, and Museum grounds alike!

Special thanks to Dr. Regina Wetzer, Director of the Marine Biodiversity Center, for identification.

Tuesday, April 5, 2011

New Fly for North Campus

Insect Trapping

To better understand the insect diversity of the North Campus, we've started surveying the insect fauna on the construction site. A few months ago, Dr. Brian Brown, the Museum's Curator of Entomology, set up a Malaise trap. This type of trap is commonly used by entomologists to capture small flying insects, and so far we've collected hundreds! One of the coolest (at least in Brian's opinion, and now mine too) is the Boatman Fly.
  
Dr. Brian Brown setting up a Malaise trap in his backyard
(yes Entomologists take their work home with them too!)

The Boatman Fly, Pogonortalis doclea, is a small (1/4 inch) fly originally from Australia. It was first recorded in California in 1963, and to date has not been recorded in any other state.  These flies are quite striking in appearance with their brightly colored eyes and highly patterned wings. Males of the species are often seen walking over leaves waving their wings in display, which look very much like a person rowing a boat, hence the name.

Boatman Fly, Pogonortalis doclea


Friday, April 1, 2011

New Bird For North Campus List

165 and Counting...

Earlier this week, Kimball Garrett, NHM Ornithology Collections Manager, spotted a not-so-common sight, a pair of Rufous Hummingbirds, Selasphorus rufus, in the Rose Garden. This hummingbird species is now number 165 on Kimball's Exposition Park Checklist. Over the last 28 years, Kimball has been keeping track of all the birds he sees in Exposition Park, even those that are just doing a fly-over!
Male Rufous Hummingbird

An Annual Migration

Most of the year Rufous Hummingbirds cannot be found in our region, but in March and April they are often seen passing through. Every year this bird makes an over 3,000 mile migration from its overwintering grounds in Mexico to the Pacific Northwest. It is easily confused with one of our local hummingbirds, the Allen's Hummingbird, and so is often missed in species counts (maybe that's why it has only just made it onto Kimball's checklist). Males of both species have red-brown markings on their sides and tails, but only the Rufous Hummingbird also has them on its back. If you have a hummingbird feeder in your yard, keep your eyes open for this hummingbird stopping by to fuel up!