The yellow-crowned night heron is a medium-sized heron that inhabits wetlands and coastal areas in North America. Assessing the rarity of this species requires looking at its conservation status, population trends, breeding range, and field observations.
Conservation Status
The yellow-crowned night heron has a conservation status of Least Concern according to the International Union for Conservation of Nature (IUCN). This means the species is not currently considered at risk of extinction. However, localized populations may be declining in certain areas due to habitat loss and disturbance.
IUCN Red List Category
The IUCN Red List categorizes species into different levels of endangerment based on criteria such as population size, range, and rate of decline. The yellow-crowned night heron falls into the Least Concern category, which is the lowest level of endangerment.
Population Trend
The overall population trend for the yellow-crowned night heron is currently stable and not decreasing at a sufficient rate to be considered threatened. However, the population in California, Oregon, and Washington is estimated to be declining.
Range and Population
The yellow-crowned night heron has a large range across North America, Central America, and the Caribbean. However, its breeding range is more limited as the species requires wetland habitat to nest.
Breeding Range
The yellow-crowned night heron’s breeding range extends along the Atlantic, Gulf, and Pacific coasts of North America, with isolated inland populations around lakes and wetlands. Its range reaches from southern New England across to southern California and south into Central America.
Population Size
The total population of yellow-crowned night herons is estimated to number between 550,000 – 1,500,000 mature individuals. The species has a large population, but it is unevenly distributed across its breeding range. Local populations can suffer declines when wetland habitat is lost or degraded.
Density
Breeding densities for the yellow-crowned night heron vary across its range. One study in South Carolina found densities ranging from 0.15-5.46 pairs per hectare across different colony sites. Densities are highest in protected coastal wetland habitats.
| Location | Pairs per hectare |
| Texas coast | 0.72 |
| Florida coast | 1.6 |
| South Carolina coast | 0.15-5.46 |
Field Observations
Assessing the relative rarity of the yellow-crowned night heron requires synthesizing data from bird surveys, checklists, and field observations. Though widespread, the species occurs in low to moderate numbers compared to other heron species.
Christmas Bird Counts
Analysis of Christmas Bird Counts provides insight into winter population trends. The average number of yellow-crowned night herons observed per count is relatively low compared to other aquatic birds:
| Species | Average # Birds per Count |
| Mallard | 688 |
| Ring-billed Gull | 504 |
| Yellow-crowned Night Heron | 7 |
Relative Abundance
In general, the yellow-crowned night heron is considered uncommon to fairly common within its coastal range by bird watchers and ornithologists. It ranks between uncommon and common compared to other heron species observed in surveys:
| Species | Relative Abundance |
| Great Blue Heron | Very Common |
| Green Heron | Fairly Common |
| Black-crowned Night Heron | Common |
| Yellow-crowned Night Heron | Uncommon to Fairly Common |
State and Provincial Lists
The yellow-crowned night heron appears on state/provincial bird lists with an average relative abundance of uncommon to common. Its status ranks as follows for select states and provinces:
| State/Province | Abundance |
| California | Uncommon |
| Texas | Common coastal, rare inland |
| Wisconsin | Uncommon |
| Ontario | Fairly Common |
| Nova Scotia | Rare |
Conclusion
In conclusion, while the yellow-crowned night heron has a wide distribution across North and Central America, it occurs in relatively low numbers compared to other wetland bird species. Conservation assessments categorize its populations as stable and its status as Least Concern. However, habitat loss and disturbance affect local breeding populations. Within parts of its breeding range, the yellow-crowned night heron ranks as uncommon to fairly common, reflecting its specificity to wetland habitats and moderate overall abundance.
