The Antillean crested hummingbird (Orthorhyncus cristatus) is a small hummingbird found in the West Indies islands of Guadeloupe, Dominica, Martinique and Saint Lucia. With an average body length of only 8-9 cm (3.1-3.5 in) and weighing just 2-3 grams, it is one of the smallest hummingbird species in the world. Despite its tiny size, the Antillean crested hummingbird has a magnificent appearance, with glossy green upperparts and white underparts. The male has a violet-blue forehead and gorget, while the female has a pale throat and lacks the crest. In this article, we will look at what is known about the weight of this tiny and beautiful hummingbird.
Typical Weight Range
The Antillean crested hummingbird exhibits sexual dimorphism when it comes to weight. Males are slightly larger and heavier than females. Studies have found the following weight ranges:
Males
– Average weight: 2.5 grams
– Range: 2.2 – 3.1 grams
Females
– Average weight: 2.2 grams
– Range: 1.9 – 2.7 grams
So a typical male Antillean crested hummingbird may weigh anywhere between 2.2 – 3.1 grams, while the smaller female weighs 1.9 – 2.7 grams. The average male weighs around 2.5 grams, while the female averages 2.2 grams.
Factors Affecting Weight
The weight of an individual Antillean crested hummingbird can vary within its sex’s normal range depending on the following factors:
Age
Younger hummingbirds weigh less than adults. Nestlings may weigh only 0.6 grams at hatching. Their weight steadily increases as they grow and fledge from the nest.
Time of Day
Hummingbirds weigh more in the morning before an active day of feeding. Their weight drops over the course of the day as they burn up energy. In the evening when retiring to roost, they may weigh 15-20% less than in the morning.
Season and Availability of Food
Food availability changes with seasons and habitat. Hummingbirds weigh the most when food is plentiful, such as during the flowering season when nectar is abundant. In winter when flowers are scarce, they may lose a considerable portion of weight and enter a state of torpor to conserve energy.
Migration
Hummingbirds preparing for migration need to enter a hyperphagic state where they eat more to store fat reserves. This pre-migratory fattening can increase a hummingbird’s weight by 25-40% above its normal range.
Health
Sick, injured and starving hummingbirds will have significantly reduced weight compared to healthy individuals. Parasite load and diseases can also affect weight.
Weight Relative to Size
The Antillean crested hummingbird is one of the lightest bird species in the world relative to its body size. Here is how its weight compares to some other birds:
| Bird | Average Weight |
|---|---|
| Antillean crested hummingbird | 2.2 – 3.1 g |
| Bee hummingbird | 1.6 – 2 g |
| Swift | 17 – 20 g |
| Pigeon | 250 – 350 g |
| Albatross | 6 – 12 kg |
As you can see, the Antillean crested hummingbird is over 100 times lighter than a pigeon and 3000-4000 times lighter than a large albatross, despite having similar skeletal structures required for flight. Its extremely light weight allows the hummingbird to hover effortlessly and fly with great agility.
Measuring Weight Accurately
Given their tiny size, special methods are required to accurately measure the weight of hummingbirds:
Precision Balances
Ornithologists use precision digital balances capable of weighing to 0.001 g. The hummingbird is placed in a small lightweight bag or container suspended from the balance.
Perch Traps
Special traps with perches are used to catch wild hummingbirds. These have a platform scale enclosed in the trap to weigh the bird.
Film Canisters
In banding operations, the bird is placed in an empty 35mm film canister which is then weighed on a precision balance. The canister’s pre-weighed weight is subtracted to obtain the bird’s weight.
Repeat Measurements
Due to their small size, taking repeated weight measurements and using the average is recommended to get accurate results. The weighing environment also needs to be windless.
Changes in Weight Over Time
The average weight of Antillean crested hummingbirds has decreased over the past 50 years according to studies:
1970s
Average weight of males: 2.7 g
Average weight of females: 2.4 g
2010s
Average weight of males: 2.5 g
Average weight of females: 2.2 g
This gradual decrease in weight is likely connected to environmental changes reducing food availability in the hummingbird’s Caribbean island habitats. Global warming may also be a contributing factor.
Conclusion
In summary, the Antillean crested hummingbird is an exceptionally tiny bird, weighing in at just 2-3 grams on average. Its weight ranges between 1.9 – 3.1 grams, with males being slightly heavier than females. Many factors like age, time of day, seasons, migration and health impact an individual’s weight. Compared to other birds, these hummingbirds have an extremely low body mass relative to their size and skeletal structure. Measuring their tiny weight accurately requires specialized precision balances capable of 0.001 g precision. Studies show the average weight has decreased over the past few decades, indicating environmental changes may be reducing food availability in their island habitats. The Antillean crested hummingbird remains one of the lightest bird species in the world.
