More Entries In Southern California

Posted at 2:25 pm May 21, 2008 by Joseph Brandt

Continuation from More Nests in Southern California.

More nests translate to a greater challenge for the field crew to monitor the nests and the movements of each pair as they take turns foraging for food over the backcountry of Santa Barbara, Ventura, Kern and Los Angeles counties. Monitoring the nests closely can provide cues in behavior that might indicate there is a problem with the egg or chick.

Nest guarding means that we have chosen to take an active and direct role in increasing chances of successfully fledging chicks from wild nests. This effort increases the number of wild fledged condors in the population and increases chances of future nests’ success by the breeding pairs. These wild fledge chicks tend to integrate into the wild population quicker than their counterparts raised at the breeding centers, due to being led by their parents from their natal areas and guided out to forage sites. Entering nest sites to prevent failures also allows us to collect important information about why and how nest failure has taken place in the past. This information will be crucial to discovering long-term solutions to the breakdown in nesting attempts and further aid in recovery of the species in the wild.

The first two interventions needed have been in the form of egg transplants. An egg transplant is the process by which an unhealthy or infertile egg is removed from the nest and replaced with a model or dummy egg. This dummy egg keeps the pair attentive to the nest until a healthy egg from one of the breeding centers begins to hatch. This hatching egg is quickly swapped out with the model egg. The pair then becomes the foster parents of a new chick, which usually finishes hatching in a day or two. Allowing the pairs to continue in their nesting attempt increases chances of success in future years because they can continue to gain experience in chick rearing behaviors and strengthen the bond they share as parents.

The first egg transplant occurred at the nest of condors 79 and 247. Having performed a fertility check on this first-time pair we were hopeful that this pair’s egg would hatch on its own, but this was not the case. After observers failed to see it hatch beyond its due date, a nest entry team was sent in to take a closer look. This team consisted of Mike Clark, a Los Angeles Zoo condor handler and I.

During the hatching process, the chick can sometimes become incapable of freeing itself from the confines of its shell and the condor parents assist in this process. If this was the case on this entry we could also assist in the process, unfortunately when we arrived at the nest we found that the egg’s development was interrupted before it came close to hatching. This can occur for a number of reasons and our best chance of determining why would be to collect the egg and take a closer look by sending the egg to the San Diego Zoo’s Pathology Lab.

We left a dummy egg for condor No. 79, who took to it like it was her own (see video below). I returned the following day with an egg from the Los Angeles Zoo that was beginning to hatch. On March 28, a day and a half after completing the transplant the first wild chick of the season was hatched and the parents are dutifully caring for the young condor.

Condors 107 and 161 chose a difficult nest to observe this season. The cavity is very dark and when the birds enter it they disappear from view. The egg is never visible so an entry was necessary in order to determine hatch. After a few days past the hatch date we entered the nest to check. While we anticipated finding a chick, unfortunately the egg had also failed to hatch. We contacted our partners at the breeding facilities to locate the next available egg that would be ready to hatch to place into this nest site. It took transporting an egg all the way from the Peregrine Fund’s World Center for Birds of Prey in Boise Idaho.

This egg was due to hatch 20 days beyond the pair’s original egg’s hatch date. Incubating condors will usually tend their nest beyond the normal period of 57 days that it takes a condor egg to hatch but their behavior can become less and less predictable as time passes. There was a risk the pair would lose interest and abandon the dummy egg so nest observers closely tracked the behavior of the pair to determine whether they were showing any signs of abandonment.

The route to this nest site is one of the most challenging to access especially when having to take extra care in transporting a hatching egg. Condor country is some of the most difficult terrain to travel through on foot. The steep canyons scattered with poison oak often require ropes to bypass, and the thick vegetation can force you to a crawl for hundreds of meters through thick chaparral and shrub lands. Dropping many hundreds of feet in elevation down one side of a canyon and climbing up the other side to position ourselves above the nest was a difficult endeavor. Luckily, the nest was a short 20 foot rappel down a 200 foot cliff.

The nest cavity is one of the largest I’ve ever seen. It is close to 20 feet at it deepest and 15 feet at it’s widest. There are spots that I was able to stand up completely straight inside the nest cave. It is no wonder we could not see the egg as it was far back inside the cavity. The female perches in a nearby tree closely watching me as I disappear into her cavity. As I swap eggs the chick noisily makes its presence known:

Condor 161, hearing the chick inside the egg, enters the nest and is interested in the noisy egg. She watches me closely as I ascend back to the top of the nest cliff. Once there, I take cover out of sight until the nest observer radios to tell me she has disappeared into the cavity. She does so after about 20 minutes of standing at the cavity entrance probably trying to determine if I plan on returning. While I am waiting I can still hear the hatching chick from time to time calling for her attention. When it is clear that I am no longer a threat she disappears into the darkness of the cavity and tends to her nest for the next three hours straight.

It will take the chick about two more days to completely hatch from the egg. Condor 161 tends to the nest for the rest of the day and through the night. The following day, her mate, condor 107, returns from a foraging trip and exchanges with condor 161. We will probably not see the chick until its 30-day checkup but the pair’s feeding behavior and continual attendance is a sure sign of a successful hatch and our second wild chick of the season.

Program Wide Support…

The Los Angeles Zoo and the Peregrine Fund helped save these wild nests from failure by supplying hatching eggs to put into wild nest sites, but any of the breeding programs (San Diego Zoo’s Wild Animal Park and/or Oregon Zoo) would have given their support. Normally these eggs would have hatched at these centers and gone on to become condors that we could one day release. Instead these chicks will fledge as if they were wild chicks with parents that will care for them and teach them the skills needed for survival in the wild. The incredible teamwork by recovery program staff and the contributions of countless volunteers’ hours has brought us two chicks closer to another successful breeding season and another step towards recovery of this magnificent species.

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2 Responses to “More Entries In Southern California”

  1. Holly says:

    What a great story! Keep up the posts … and keep away from poison oak!

  2. njr says:

    Great update - you and your team are to be commended for the extraordinary efforts you make to check on the eggs and to provide replacements for failed eggs so that both the parent birds and the replacement chicks can benefit. Sometimes nature needs a helping hand! Hope you can report back on what caused the egg development to halt. Has this happened for previous eggs and if so, is there a common cause for it?

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