Air Wars

Understanding Seabird Behavior Leads to Impressive Catches

FSF Staff May 27, 2013

When it comes to finding marine life in the open ocean, nothing sets the stage quite like a flock of seabirds carefully scanning and working the surface. Frigates, terns, seagulls, petrels, gannets and shearwaters are only a few of the species you will encounter along Florida’s fertile offshore waters. By identifying and observing bird activity from a distance, seasoned captains can make accurate estimates of the correlating action in the sky to what is actually unfolding below the surface.

air-wars1

1 of 5

Photo: Scott Kerrigan

With nearly 70 percent of the Earth’s surface covered in saltwater, anglers have a lot of ground to cover. Some stretches of water teem with life, while others are nearly lifeless. The game fish we seek are attracted to a few key features and to be successful in your offshore adventures you’ll need to focus on promising stretches of water featuring fish holding structure. This includes both underwater structure as well as surface floating debris, current breaks, color changes and the presence of baitfish—all of which can be pointed out by squawking seabirds.

Their height over the water can also signal some interesting clues, with birds working close to the surface usually shadowing small fish that are easy to track.

Pelagic seabirds spend a majority of their lives covering wide open stretches of water and are highly adapted to survive in the harsh marine environment. All seabirds have hollow bones that enable them to effortlessly glide for miles, with some species specially adapted to drink saltwater with the ability to excrete salt from a specialized gland. Most seabirds also feature webbed feet and have feathers that are coated with oil to repel water. Seabirds feed almost exclusively on fish, squid and crustaceans, but they vary in their hunting techniques and related physiological features. No matter how they do it, birds are effective fishermen and provide a wealth of valuable knowledge. You just have to know how to decipher what you see.

Starting with the most prized sights offshore, frigate birds are distinguished by their large wingspan, swallowtail and unmistakable black silhouette. Frigates are unique in the fact that they are perfectly adapted to cover large areas of water with their giant wingspan that’s proportionately larger than any other bird’s wing to body mass ratio, yet their thick plumage doesn’t have the same waterproof coating as other seabirds. As a result, frigate birds cannot touch down in the water or they risk not being able to relaunch. Because of this, frigate birds are forced to scavenge or delicately pluck baitfish off the surface with their elongated beaks. Because of the frigate bird’s unique hunting strategies, observant anglers have determined that frigates typically follow predators, not baitfish.

Frigates have little chance following and capturing fast moving forage that rarely come within reach of the surface without predator interaction, so they simply follow large pelagic game fish and wait for them to find and push potential food to the surface. Because of their limited hunting abilities, frigate birds are also commonly seen harassing other birds in an attempt to steal their catch. When you see a frigate working close to the surface you know it’s for a good reason. If a frigate is circling high in the sky it is likely waiting for predators to once again force bait to the surface. It’s also important to note that with amazing eyesight, frigates may be upwards of a quarter mile from the game fish they are tracking.

Terns are another species you will encounter in the open ocean. Like frigates, terns do not like to get wet since they lack waterproof plumage. Sooty terns are some of the most numerous in our region and rather than diving into the water, these capable seabirds fly low to the surface and simply pluck baitfish that leap into the air to avoid predation from below.

Bridled terns are yet another species you will encounter, yet unlike sooty terns they can be seen perched on flotsam. All terns display noticeable strategies when searching for forage and if you see them circling a spot several times it’s likely there are predator fish below. Not only fish locaters, terns point the way to weedlines and surface debris since they are opportunistic feeders that will take any chance to eat. Shearwaters, petrels and gannets are additional birds you’ll encounter when plying offshore waters.

Like game fish in their element, birds possess several key hunting advantages, of which the most beneficial is the extended visibility afforded by height. However, certain species of birds have also been determined to have powerful olfactory organs, enabling them to key in on oily baitfish. Research has shown that shearwaters and petrels can smell surprisingly well. These birds are classified with a group of tube nosed birds and it has been determined that some can sniff out a potential meal from upwards of 30 kilometers!

Now that you know what birds to look for, by observing the movement of the birds you can also get a good idea of what lies beneath. While seabirds are after the same thing and all have similar characteristics, they behave with slight variations in different venues, so as with most aspects of sport fishing local knowledge is priceless. By spending time on the water and observing bird activity in relation to what you experience you will become a more knowledgeable and successful angler.

In the Florida Keys seasoned captains can accurately determine the size of dolphin by bird behavior and their direction of travel. Tuna terns and gulls working the surface in a northerly movement generally means schoolies are likely feeding below. With birds working to the south, against the flow of the swift moving Gulf Stream, captains can tell bigger gaffers are holding since they are more capable of working and covering ground into the fast moving current. Big pairs, like mature bull and cow dolphin, typically have fewer birds following them when compared to an aggressive pack of juvenile peanuts. This is because two mature fish cannot corral bait on the surface as effectively as a gathering of fired up green hornets.

Their height over the water can also signal some interesting clues, with birds working close to the surface usually shadowing small fish that are easy to track. Three to five birds hovering a little higher are likely on larger fish because they don’t want to lose them.

Now that you have a better understanding of seabirds and their associated behavioral patterns there are a couple of ways to find their location. A quality pair of binoculars will enable you to search the horizon for bird activity, while a powerful radar will pinpoint a single bird from miles away. While a radome will work for close target acquisition, for even greater bird spotting range you’ll want an open array radar with high power output and beamwidth. The term beamwidth refers to the horizontal or vertical view of the radar pulse, and the narrower the beamwidth the greater the resolution and the more accurate the target definition. Most radome antennas have a beamwidth of 3- to 7-degrees, while open array units have a more concentrated beamwidth of 2 degrees or less. Because a wider beam will return a large, concentrated blob instead of individual marks, it will be difficult to locate single targets way out in the distance.

When dialing in your radar to spot birds you’ll want to start by adjusting the gain until you see clutter on the screen. If the gain is too high it will be hard to spot birds, while too low of a gain setting won’t return small targets like single birds. You should also turn off the rain and sea clutter settings. Once you’re dialed in you should have a light green fuzz covering your radar screen. Birds will appear as small returns with a different density. When you’ve located birds with your radar and are approaching the activity you’ll need to observe their movement and establish a plan of attack. Tracking head on will push the fish deep and birds high, so try and determine which way they are moving so you can intercept their path.

If you’re in a promising area, nearly all bird activity is worth investigating, but after spending a healthy amount of time on the water you’ll have a greater idea of what the birds are trying to tell you. Study the skies and keep an eye out for our feathered friends. With practice you’ll be able to determine which bird schools will lead the way to impressive catches and which will get you nowhere.

Join the Discussion