Sea Birds pt 2 and Sea Mammals

Seabirds Overview

Uropygial Gland:

• The uropygial gland, located near the base of the tail, is crucial for maintaining plumage health.

• It produces a waxy oil that depurates and waterproofs feathers, preventing water absorption, which is essential for buoyancy and insulation during cold water immersion.

• If the gland is non-functioning, seabirds will experience deterioration of feathers, resulting in loss of waterproofing; this can lead to hypothermia and increased mortality during harsh weather conditions.

Seagulls

• Classification: Seagulls belong to the family Laridae and are widely recognized as marine birds, although they are also seen inland.

• Habitat: These birds inhabit a variety of environments, including coastlines, beaches, and urban areas, thriving in regions where food sources are abundant.

• Behavior: Known as opportunistic scavengers, seagulls are often seen congregating around human food waste, making them a common sight at beaches and picnic areas.

• Diet: Their diet is highly adaptable, including not only scavenged food and garbage but also small fish, crustaceans, and eggs of other birds.

• Intelligence: Seagulls display remarkable intelligence, engaging in complex behaviors such as 'dancing' to provoke terrestrial earthworms to surface for feeding.

• Dependency: Contrary to many seabirds like the albatross and penguins, seagulls are less reliant on marine conditions, allowing them to thrive in varied landscapes.

Puffins

• Habitat: Puffins are predominantly found in colder waters, with significant populations off the coasts of Maine and Canada, often inhabiting rocky coastal cliffs.

• Behavior: Puffins are skilled divers and spend the majority of their time at sea, returning to land primarily for breeding.

• Breeding: This species breeds once a year during the warmer months; males exhibit brightly colored beaks to attract females. These colors fade post-breeding for better camouflage in winter.

• Beak Color Change: Puffins' bright beaks are most vivid in spring and summer, aiding in mate selection, while the dull coloration in fall/winter helps them blend into their environment.

• Diet: They display remarkable diving skills to seize a range of marine food sources, such as fish, which they catch and store in their beaks while swimming.

Shorebirds

• Characteristics: Shorebirds, including species like sandpipers and herons, are often seen along marine coasts and estuaries, making them integral to these ecosystems.

• Difference from Seabirds: In contrast to seabirds, shorebirds do not have webbed feet and are primarily active on land rather than displaying swimming behaviors.

• Habitat Use: Though they thrive in coastal zones, many shorebirds also inhabit freshwater wetlands for feeding and nesting.

Swimming and Diving Adaptations

• Body Structure: Seabirds possess streamlined bodies designed for efficient swimming, reducing drag in water.

• Leg Modifications: In adaptation to aquatic life, many seabird species have legs that are reduced in length and modified into flippers.

• Buoyancy Adaptations: Species known for diving often have heavier bones, which assists them in submerging rapidly while hunting for prey underwater.

• Oxygen Management: The circulatory systems of diving seabirds feature increased red blood cells and hemoglobin concentrations, enabling prolonged dives with limited oxygen availability.

Reproductive Characteristics

• Mating Behavior: Many seabird species, including seagulls, exhibit long-term pair bonds by mating for life, though divorce can occur if nesting attempts fail.

• Courtship: Courtship rituals are integral, involving elaborate displays and the exchange of gifts (food or nesting materials) to reinforce pair bonds.

• Parental Care: Parental roles are significant in seabird rearing; males frequently assist in incubation duties and are involved in caring for chicks post-hatching, ensuring they receive adequate food and protection from predators.

Marine Mammal Introduction

• Characteristics: All marine mammals, including dolphins and seals, are characterized by having hair at some life stage, are endothermic, and possess adaptations for life in aquatic environments.

• Distinctive Features: Marine mammals commonly possess blubber, which serves as insulation in cold waters and as an energy reserve when food is scarce.

• Intelligence: These mammals exhibit advanced social structures and cognitive behaviors, with reported instances of tool use (e.g., sea otters utilizing rocks to crack open shellfish).

Groups of Marine Mammals

• Phocids: This group includes seals, known for adaptations such as blubber and streamlined bodies for swimming.

• Otariids: Comprising sea lions and walruses, these mammals have external ear flaps and are often more agile on land than phocids.

• Carnivorous Mammals: Includes species such as sea otters and polar bears that have diets primarily consisting of marine organisms.

• Sirenia: This group includes manatees and dugongs, known for their herbivorous diets and reliance on coastal seagrass beds.

• Cetacea: Dolphins and whales represent the most adapted marine mammals for aquatic life, showcasing complex communication systems and social structures.

Adaptations for Diving

• Diving Abilities: The diving capabilities of marine mammals vary widely; for example, the Northern Elephant Seal can dive to depths of up to 1,500 meters and hold its breath for over an hour.

• Breathing Adaptations: Marine mammals utilize specialized breathing techniques that allow for rapid oxygen intake and efficient expulsion of carbon dioxide during surfacing bursts.

• Muscular Adaptations: Enhanced myoglobin content in muscles of diving mammals aids in oxygen storage, further supporting extensive and deep dive durations.

• Heart Rate Control: The physiological phenomenon known as bradycardia, which involves a significantly reduced heart rate during dives, optimizes oxygen use and reduces metabolic demand during lengthy submersions.