Do Seabirds Drink Salt Water? A Quiet Guide for Prairie Birdwatchers

Yes, many seabirds can drink salt water safely, but they do not simply absorb the salt. Instead, they use specialised salt glands to remove excess salt from their blood, a process called osmoregulation. This allows species like gulls, pelicans, and some shorebirds to thrive in marine and saline environments—including the saline lakes and alkali flats of the prairies—without needing a steady supply of freshwater.

What Happens When a Seabird Drinks Salt Water?

When a seabird swallows salt water, its body absorbs both water and salt through the gut. To keep its internal salt concentration within a safe range, the bird must excrete the extra salt quickly. In birds that regularly encounter salt water, the salt glands—located above the eyes, in shallow grooves in the skull—take over this job. These glands pump a concentrated salt solution out through the nostrils. The fluid is often seen dripping from the bill tip, especially after the bird has been feeding in salt water or drinking from a saline lake.

How Do Salt Glands Work in Seabirds?

Salt glands act as a biological desalination system. They remove sodium and chloride ions from the bloodstream and secrete them as a fluid that is roughly two to three times saltier than seawater. The glands are activated by rising blood salt levels. Once triggered, the bird may shake its head or sneeze out the salty droplets. This is a normal, efficient process that allows the bird to use salt water as a hydration source when freshwater is scarce.

Which Birds Use Salt Glands on Saline Lakes and Alkali Flats?

On prairie saline lakes and alkali flats, you may see several bird groups that rely on salt glands:

• Gulls and terns (family Laridae) are common at alkaline lakes and often drink saline water.
• Pelicans (American white pelican) have well-developed salt glands and can drink from brackish or saline water bodies.
• Some shorebirds, such as avocets and stilts, have functional salt glands and use saline habitats for feeding and nesting.
• Certain ducks and grebes can tolerate saline water through salt glands, though many still seek freshwater for drinking when available.

In contrast, songbirds and most freshwater-dependent species lack effective salt glands and must find freshwater to survive.

Osmoregulation: Keeping the Balance

Osmoregulation is the active regulation of water and salt concentrations in an organism's body. For seabirds, this means balancing water gained from drinking and food against water lost through respiration, excretion, and salt gland secretion. When a bird drinks salt water, osmoregulation ensures that blood salt levels do not rise dangerously. The salt glands excrete the excess, while the kidneys conserve water by producing highly concentrated urine. This dual system allows seabirds to exploit environments where freshwater is limited or absent.

What to Notice in the Field: Signs of Salt Gland Use

On a quiet morning at a prairie saline lake, you can observe salt gland activity without disturbing the birds. Look for:

• Clear fluid dripping from the bill tip of a gull or pelican after it has been drinking or feeding in the water.
• Head shaking or sneezing motions that expel salty droplets.
• Birds resting with their bills slightly open, allowing the salty secretion to drain.

These behaviours are normal and indicate the bird is managing its salt load. They are most visible on warm, dry days when birds drink more frequently.

Freshwater Sources: A Vital Resource on the Alkali Flats

Even birds with functional salt glands need some freshwater at times, especially during nesting or when feeding young. Chicks may not have fully developed salt glands and depend on parents to bring freshwater or low-salt food. In arid prairie regions, natural seeps, springs, rainwater puddles, or even dew on vegetation can be critical. Birdwatchers can note the location of nearby freshwater sources and watch how birds move between saline feeding areas and freshwater drinking spots.

Seasonal Changes in Salt Water Use

The need to drink salt water changes with the seasons. During spring and summer, higher temperatures increase water loss through panting, so birds may drink more saline water and rely more heavily on salt glands. In wetter periods or after heavy rain, temporary freshwater pools appear, and birds may switch to these easier sources. In autumn, as many species migrate, they may stop at saline lakes to refuel, using salt glands to process the salty water and prey.

Practical Tips for Your Next Outing

1. Bring binoculars and a field notebook; salt gland secretion is best seen at close range but without disturbance.
2. Visit saline lakes early in the morning or late afternoon when birds are actively drinking and feeding.
3. Keep a respectful distance—use a spotting scope if available. Stress can disrupt normal osmoregulation behaviour.
4. Look for freshwater seeps or puddles near the shoreline and note which birds use them.
5. Record weather conditions, as hot, windy days increase saline water intake and visible salt excretion.
6. Compare species: watch how a gull and a duck respond differently to the same saline water.

Comparison: Birds That Drink Salt Water vs. Birds That Cannot

Caring for Birds and Their Saline Habitat

Respectful observation means staying on established paths and avoiding nesting areas on alkali flats. Saline lakes are fragile ecosystems; trampling vegetation or disturbing shoreline crusts can reduce freshwater microhabitats. Pack out all trash, keep dogs leashed, and never approach birds so closely that they flush. Quiet, patient watching often reveals the most interesting behaviours, including salt gland use and osmoregulation in action.