<em>By Victoria McCloskey, Biologist
California Academy of Sciences, Steinhart Aquarium
55 Music Concourse Drive, San Francisco, CA, USA</em>

The rainforest exhibit at the California Academy of Sciences is a free-flight, mixed-species display that is a 90-foot diameter glass sphere. The space includes one large open-topped pool with live fish, two planted beds, an elevator system, and a ramp that extends from level one to level three.  The birds are exhibited along with live butterflies, so the exhibit itself is a USDA containment room.  The birds have access to nearly everything within the glass containment walls.

The exhibit is staffed by two aviculturists, three herpetologists, two horticulturists, three aquarists, and two generalists.  Each level boasts numerous terrariums and fish tanks that are serviced daily before opening to the public.

We have overcome a myriad of challenges since opening this exhibit in September of 2008.  In addition to the stresses of introducing a variety of species at one time, biologists had to contend with a 360-degree glass sphere, feeding free-flying birds and butterflies, and navigating a 100,000-gallon, open-topped freshwater fish tank that houses bird-eating fish such as pacu (<em>Colossoma macropomum</em>), arawana (<em>Osteoglossum bicirrhosum</em>), and arapaima (<em>Arapaima gigas</em>).

<strong>Introductions</strong>
Introducing a number of animals all at once is always a dicey proposition.  The stress of introducing approximately 35 individuals of different species was only compounded by having to release them into a giant glass sphere.  This posed the problem of how to minimize injuries from birds accidently flying into the glass.  Many ideas were considered – decals, spray ‘snow’, etc.  We finally formalized a plan whereby the entire exterior of the structure would be covered in shade cloth.  This was a huge undertaking, as the circumference of the sphere is formidable.  We also hung shade cloth in front of the galleries on each level in order to prevent birds from getting ‘lost’ or ‘stuck’ when they were first released.  Consequently, on initial release there were no deaths from glass strikes.

Species were housed according to size/compatibility, and howdied in the exhibit for a few days before the doors were left open allowing the birds to venture out at will.  The smaller species such as honeycreepers (<em>Cyanerpes cyaneusm, Cyanerpes caeruleus</em>), violaceous euphonias (<em>Euphonia violacea</em>), paradise tanagers (<em>Tangara chilensis</em>) and opal-rumped tanagers (<em>Tangara velia</em>) were released first to give them a chance to establish territory and find safe roosting areas.  These were followed by the larger more aggressive species such as silver-beaked tanagers (<em>Ramphocelus carbo</em>), red-shouldered tanagers (<em>Tachyphonus phoenicius</em>), turquoise tanagers (<em>Tangara mexicana</em>) and saffron finches (<em>Sicalis flaveola</em>).  The last species to be given access was the blue ground dove (<em>Claravis pretiosa</em>).

As expected, there were multitudes of dynamics between individuals.  We lost a few birds to male/male aggression fairly quickly.  The silver-beaked tanager, and surprisingly, the violaceous euphonia males killed the other resident males of their species within days upon release.  We also noted immediate aggression between the lone saffron finch and the yellow-green grosbeaks (<em>Caryothraustes canadensis</em>).  This aggression escalated when five more saffron finches from another facility were introduced at a later date.  Unfortunately, when the flock increased from one individual to six, the grosbeaks were targeted directly and had to be removed from the exhibit.  We assume color was the instigating factor.

The only ground species that was introduced into the original population was the blue ground dove.  This species tends to fly ‘up’ when startled, and after losing a significant number of individuals to trauma induced injuries, we returned the remainder of the population to the breeder.  Due to limited planted exhibit space, we chose not to pursue introducing any additional ground species.

<img class="alignnone size-full wp-image-1928" title="butterflies" src="http://aecetia.net/gws/aazk/wp-content/uploads/butterflies.jpg" alt="butterflies" width="814" height="504" />
<p style="text-align: left;"><strong><em>Heliconus sp.</em> at nectar feeders</strong> <em>(Photo courtesy of California Academy of Sciences)</em></p>

<p style="text-align: left;"><strong>Feeding</strong>
We had to devise a system that would permit not only the passerines access to food on multiple strata, but also the butterflies.  Free standing feeders in the ground level planters were inaccessible to the public, and fairly easy for biologists and birds to access.  More challenging however was how to have food and nectar available on the two upper levels. There is no floor space on these levels that the public does not have access to, therefore we created feeders that would hang from the railings over open space.  The feeders were thin metal rods with plate-sized metal rings on the end.  These were welded to the railings on levels 2 and 3, and were able to swing out and back for access.  A locking pin holds them in place so that they remain stationary until a biologist changes the plates.

Our original idea was to be able to set the plates inside the rings.  The drawback to this arrangement was that the plates occasionally got knocked out and fell.  It didn’t take us long to figure out that plates and nectar containers would have to be plastic. After trying a few different prototypes, we found that a plate with a locking mechanism was the best bet, so we changed the holder to a flat disc with a central hole.  The food plates have central plastic pins that lock them onto the discs with a quick twist.  We also found an ideal length for the metal rod – long enough that the public could not lean over and reach the food, but short enough that stability was not compromised.

The birds are fed a fresh fruit and vegetable mixture along with pellet and softbill diet.  Insects are offered daily - mealworms, phoenix worms or waxworms.  As the exhibit is now inhabited by nuisance ants that seem to be attracted to crickets, these insects are no longer on the menu. Nectar is offered in the morning, oranges in the afternoon.  The butterflies quickly ‘learned’ where the nectar stations were.  Finding a container that would hold an appropriate amount of nectar, but was not so deep that the butterflies would drown was an ongoing concern for the biologists.  After many different designs we finally concocted one that ………….

<em><strong>Want to read the rest of this important and informative article? For this and many more fascinating articles every month, see Animal Keepers’ Forum.  AKF is available only by being a member of AAZK. <a href="http://aecetia.net/gws/aazk/join/">JOIN NOW! </a></strong></em>