| Birds Name | Yellow-shouldered blackbird |
| Science Name | Agelaius xanthomus |
| Domain | Eukaryota |
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Aves |
| Order | Passeriformes |
| Family | Icteridae |
| Genus | Agelaius |
| Species | A.xanthomus |
The Yellow-Shouldered Blackbird (Agelaius xanthomus), known in Puerto Rican Spanish as “mariquita de Puerto Rico” or “capitán,” is an intriguing species endemic to Puerto Rico.
The Yellow-Shouldered Blackbird is a striking bird with unique features that set it apart from other blackbirds.
- Plumage: Glossy black with a prominent yellow patch on the wings, outlined by a white margin. Immature individuals have duller coloration and a brown abdomen.
- Size: Adults measure 20-23 cm (7.9-9.1 in) in length.
- Weight: Males average 41 g (1.4 oz), while females weigh around 35 g (1.2 oz).
- Sexual Dimorphism: Males are larger than females, and their wings are 1.1 times longer, with a mean length of 102 mm (4 in) compared to females’ 93.3 mm (3.7 in).
Taxonomy
- Scientific Name: Agelaius xanthomus
- Family: Icteridae
- Genus: Agelaius
- Species: xanthomus
- Subspecies:
- A. x. xanthomus (Nominate form from Puerto Rico and Vieques)
- A. x. monensis (Mona Yellow-Shouldered Blackbird from Mona and Monito Islands)
The species was first described in 1862 by Philip Sclater as Icterus xanthomus. The subspecies A. x. monensis was described by Barnes in 1945.
Distribution, Range, and Population
The Yellow-Shouldered Blackbird is endemic to Puerto Rico, with populations on the main island and the smaller islands of Vieques, Mona, and Monito.
| Region | Presence |
|---|---|
| Puerto Rico | Common |
| Vieques | Common |
| Mona Island | Common |
| Monito Island | Common |
Habitat
The Yellow-Shouldered Blackbird inhabits a variety of environments but shows a preference for areas near water bodies and coastal regions.
| Habitat Type | Commonness |
|---|---|
| Mangroves | High |
| Coastal Areas | High |
| Wetlands | Moderate |
| Agricultural Fields | Moderate |
| Urban Areas | Low |
Behavior
This species exhibits notable social and behavioral traits.
| Behavior Type | Description |
|---|---|
| Social Structure | Highly social, often seen in flocks |
| Vocalizations | Various calls, including sharp, distinct notes |
| Foraging | Ground and tree forager, insectivorous |
Feeding
The Yellow-Shouldered Blackbird is primarily insectivorous but has a varied diet.
| Food Type | Percentage of Diet |
|---|---|
| Insects | 70% |
| Fruits | 15% |
| Seeds | 10% |
| Other | 5% |
Breeding
Breeding behaviors and practices of the Yellow-Shouldered Blackbird.
| Aspect | Details |
|---|---|
| Nesting Location | Trees, shrubs, sometimes ground |
| Clutch Size | 2-4 eggs |
| Incubation Period | 12-14 days |
| Fledging Period | 15-18 days |
Threats
Despite being relatively stable, the Yellow-Shouldered Blackbird faces several threats.
| Threat Type | Impact Level |
|---|---|
| Habitat Destruction | High |
| Predation | Moderate |
| Climate Change | Moderate |
| Human Disturbance | Moderate |
Migration
The Yellow-Shouldered Blackbird is mostly sedentary, with limited migratory behavior.
| Season | Migration Pattern |
|---|---|
| Spring | Minimal migration, local movements |
| Fall | Minimal migration, local movements |
Comparison with Similar Species
| Feature | Yellow-Shouldered Blackbird | Tawny-Shouldered Blackbird |
|---|---|---|
| Plumage | Glossy black with yellow shoulder patch | Black with tawny shoulder patch |
| Size | 20-23 cm (7.9-9.1 in) | 24 cm (9.4 in) |
| Social Behavior | Highly social | Highly social |
| Habitat Preference | Mangroves, coastal areas | Similar habitats |
Conclusion
The Yellow-Shouldered Blackbird is a distinctive and important species in Puerto Rico’s avian biodiversity. Its unique appearance, behavior, and ecological role make it a fascinating subject for bird enthusiasts and researchers alike. Conservation efforts are crucial to ensure the continued survival of this species amidst the challenges posed by habitat destruction and other environmental threats.