The Feeding Frenzy

What is the feeding frenzy you might be asking? The feeding frenzy at Corkscrew is when there is an overwhelming amount of prey that attract a high amount of predators. Several species of wading birds, snakes, alligators, and mammals show up to eat the plentiful fish in the ponds. To understand why the feeding frenzy occurs, you need to understand the hydrology behind the phenomenon. 

Our dry season at Corkscrew is December-May where water levels decrease rapidly. However, our bodies of water don't actually start drying up until March. In March and April, water levels at Corkscrew decrease to the point that most of the water completely dries out. As the water continue to dry down, it traps high amounts of fish in small pockets of water with nowhere to go. 

With the decreasing water levels in these ponds and the high density of fish, this is the perfect opportunity for the wildlife at Corkscrew to feast on the bountiful amounts of fish, invertebrates, and other aquatic species before the rainy season starts. The wading birds especially take this opportunity to feast, and aggregate in large numbers. 

In the two-mile boardwalk at Corkscrew, we have the south lettuce lake and north lettuce lake. The picture below is what the north lettuce lake looks like when it is filled with water. This was taken on March 25, 2018 almost 3 weeks before the biggest feeding frenzy we have seen this year. 

Photo Credit: Lee Martin 3/25/2018

As you can see in this photo on the left there is still plenty of water in the north lettuce lake, however, in the following weeks the water will dramatically decrease and possibly even completely dry out. Usually throughout the year you see a handful of wading birds in the north lettuce lake like Anhingas, Little Blue Herons, and Great Egrets. You also see alligators, turtles, and snakes in the north lettuce lake. The following photos you are going to see from our feeding frenzy is quite the opposite from this first photo. 

                       April 19, 2018 FEEDING FRENZY!

Photo Credit: Melissa Gonzalez 4/19/2018

Feeding Frenzy video

 

Photo Credit: Melissa Gonzalez 4/19/2018

At 9am on April 19th, Kelsie and I did a Facebook Live on the Corkscrew page from the north lettuce lake to show our followers an update on what the lettuce lake looked like, and to educate about the feeding frenzy and hydrology. As Kelsie and I were walking towards the north lettuce lake, we could hear the loud calls of many wading birds coming from the direction of the north lettuce lake. We could feel the high energy coming from that direction and we knew it was going to be a great morning. As we got to the north lettuce lake the amount of wading birds we saw completely blew our minds. I never imagined that many wading birds at Corkscrew, and this completely exceeded my expectations. There were literally hundreds of birds in this lake! I counted over 50 Wood Storks, and over 50 Great Egrets all in close proximity of each other. Other species found in large amounts were the White Ibis, Snowy Egret, Little Blue Heron, Roseate Spoonbill, Anhinga, Tri-Colored Heron, and Great Blue Heron. The wildlife present at the north lettuce lake that day were eating high amounts of fish. I saw some Great Egrets catch decent sized fish one after the other. I could not believe that they could eat that much fish consecutively. With the amount of fish that each bird was catching I was sure that they would have eaten the majority of the fish by the end of that weekend and the wading birds would move on to the next hot spot. 



As I was staring out into the lake, I noticed that multiple birds continued flying in and adding to the large amount of birds. I looked up at the sky and saw an impressive amount of Wood Storks and Great Egrets circling, trying to search for the perfect spot to land. Just like little airplanes, intricately trying to find an open spot to land into the lettuce lake airport. I saw many Wood Storks, Great Egrets, Anhingas, and White Ibis circling the lake, and one by one they touched down. It was like they made their own Facebook event and one by one all the wading birds were flying in from different places to attend this massive feast. Check out the video below on the wading birds flying in.

To give you some perspective on how dramatic the change was overnight this is what the lettuce lake looked like the night before on April/18/2018 at 6pm. Kelsie and I were at the north lettuce lake and there were a couple of wading birds out that night. We saw Great Egrets, Roseate Spoonbills, Wood Storks, Snowy Egrets, White Ibis, and Little Blue Herons, but not even close to the amount we saw the next morning. 

Photo Credit: Melissa Gonzalez 4/18/2018

You might be wondering why there is not a feeding frenzy year round. If you think about it, usually the bodies of water at Corkscrew can get fairly deep especially after the rainy season (June-September). With the water levels being deeper, the fish are more spread out throughout the water and have more hiding spots therefore making it difficult for certain birds to catch fish. Wading birds with short legs tend to stick around shallow water and use their long beaks to forage along the bottom of the ponds as they do not want to be in deep water. Wading birds with long legs and necks such as Great Egrets and Great Blue Herons are able to get into deeper water to find their food but have the option to forage in shallow water as well. Therefore, the dry season is the perfect time for wading birds of all sizes. Because the water is shallow enough and the small bodies of water are stocked with high amounts of fish, the birds can easily catch them since there is less water and less room for hiding.

Photo Credit: Lee Martin 4/22/2018

The amount of wading birds had dramatically decreased two days later, but there were still more birds than you would regularly see in the year. Even though the amount of birds had decreased, these birds were still feasting on the fish still available. 

The rainy season will be here if not by the end of May, then in June, and these wading birds will move somewhere else. I feel very lucky that I was able to be at Corkscrew during this huge feeding frenzy. It was definitely one of the coolest wildlife experiences I have ever had, and I will come back to Corkscrew annually just to witness this amazing event. 

Thank you for reading my blog, I hope you enjoyed it!

-Melissa Gonzalez

If you are interested in watcing the Feeding Frenzy FB Live on the Corkscrew Page follow this link: https://www.facebook.com/CSS1954/videos/1935604939814679/

If you want to see a 1 minute video of the Feeding Frenzy follow this link: https://www.facebook.com/CSS1954/videos/1936402853068221/

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I am now in my third month at Corkscrew. Before I know it, it will be my time to leave this magical swamp at the end of the summer. The past 3 months have been incredible, and I truly love my internship here. I have seen what the swamp has to offer, and believe me when I say that the swamp is truly a special and important place that we must protect at all costs.

Kelsie left Corkscrew 2 weeks ago after an 8 month internship. I am really happy that I not only got to learn so much from her, but also that I was able to gain a great friendship. Good luck in your future endeavors Kelsie, the swamp will miss you!

Audubon EagleWatch Monitoring

One of my favorite things about being an intern at Corkscrew is participating in Audubon's EagleWatch with our director of public programs, Sally. EagleWatch is a citizen science program that anyone can participate in if they have a love and appreciation for eagles. The purpose of EagleWatch is to monitor Florida's Bald Eagles throughout their nesting season. As an EagleWatch volunteer, we are the lookouts for our eagles, ensuring the safety of a particular nesting pair and eventually, their chicks. The reports that are done by volunteers are beneficial to biologists, as well as law enforcement such as FWC and US Fish and Wildlife. Based on the information we provide Audubon, environmental protection leaders can determine the best way to conserve this species for the future.

I started observing our eagle's nest in November 2017 when I first started at Corkscrew. This particular nest that sits on Audubon's property is not located near the boardwalk, so unfortunately, if you are visiting the sanctuary you will not be able to see it. At this time in late November, the eagles were still building their nest back up after hurricane Irma damaged their old one. Eagles tend to return to the same nest year after year, and they weren't going to let the hurricane's damage stop them! Building the nest is a lengthy process and can take months, but both the male and the female participate in nest building. Working together reinforces their bond, and also speeds up the process!

By January, the eagles were observed sitting on their nest. We are unsure of when the eggs were actually laid, as it is impossible to see inside the nest, but we can assume it was around the first few weeks into the new year. Eagles will sit on and incubate their eggs for roughly 35 days before they hatch.

Finally, on Valentines Day, we observed that there was an eaglet! This was such an exciting moment for all who were invested in observing this nest.

This one, fluffy, dinosaur-like head popped out of the nest and we all squealed with joy. This eaglet was our first evidence of a hatchling, but we weren't sure of how many would appear since we weren't aware of how many eggs were in the nest. After another week or two of observations, we were overjoyed to see that there were actually three eaglets in the nest!

This picture was taken at the end of February, and you can see all three eaglets with their parent on the nest.

Today, our eaglets are just about two months old, and they will start branching any day now. This past week, one of the eaglets has demonstrated the beginning stages of branching. Branching is when they start flapping their wings to build muscle, and jump from branch to branch.

This picture is my most recent, and it shows all three eaglets (one is laying on the bottom of the nest, resting). They grow up so fast!

The next time we observe them, which will be by the end of this week, we expect to see at least one of the eaglets maybe in a nearby tree, branching. This has been such a beautiful process, and amazing that all three chicks have made it this far and all appear to be healthy.

Until next time,

Shelby

My day with The Croc Docs

Throughout the past few years, I have been exploring my newfound interest in reptiles and amphibians. One of the many projects we work on here at Corkscrew is the Everglades Invasive Reptile and Amphibian Monitoring Program in partnership with The Croc Docs. Unfortunately, the recent hurricane destroyed our survey route at Corkscrew, so our survey has been postponed until we can determine a new route.

My passion for amphibians and reptiles has been shared with many coworkers and guests here through my posts on Facebook and excitement when an individual is found. My boss, Dr. Shawn Clem, knew of my excitement for these species and helped set me up with The Croc Docs to go on one of their monitoring surveys! 

Last Thursday I started my morning in Davie checking tegu traps with a graduate student with The Croc Docs. The Argentine Black and White Tegu is a large, invasive lizard that has started a breeding colony in two counties in Florida. The first tegus found in the wild of Florida were believed to have been released or escaped pets. Efforts are currently in place to try to remove all individuals that are found in the wild.

During my day with The Croc Docs, 160 traps were checked and reset for another day of trapping. Two types of live animal traps are set with eggs to attract the tegu. During our sampling on Thursday, we had two individuals in the traps, and both were removed from the ecosystem. I had mixed feelings about the day - I was excited to see these huge lizards (an individual can reach up to 4 feet long!), but then I remembered that I was seeing them here because there is a large population of this invasive species. The tegu has the potential to impact threatened and endangered species such as the American Crocodile, sea turtle species, and ground nesting birds, by preying on their eggs. 

  

(Young Florida Water Snake (left) and Ring Necked Snake (right))

Later on that day, I went on a night survey with the crew for their Everglades Invasive Reptiles and Amphibian Monitoring Program. The excitement continued with sightings of many native species such as the Pig Frog, Florida Water Snake, Brahminy Blind Snake, and Ring Necked Snake, along with some native mammals such as the Marsh Rabbit, and Virginia Opossum. All these sightings are a great sign, as each of these species has the potential to be displaced by non-native species invading Florida. 

(Colorful underside of a Ring Necked Snake)

This day with The Croc Docs was fuel for my interest in reptiles and amphibians, and a small look into the grand scale of invasive species of Florida. Thank you Dr. Clem for presenting me with this opportunity, and thank you to The Croc Docs for teaching me so much! For more information on The Croc Docs and their programs, visit: http://crocdoc.ifas.ufl.edu/currentprojects/

-Kelsie  (Research Intern)