ML618380039
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Деталі спостереження
This species reaches the northern limit of its range in southern Texas where it appears to be increasing. Prior to 1950 it was considered rare. Resembling an oversized male Hooded Oriole, it is the largest oriole in the US. Texas birds are the smaller more brightly colored subspecies "I. g. tamaulipensis" formerly known as Lichtenstein's Oriole. Males and females look alike. They remain paired throughout the year and are resident. Why do migratory orioles show a strong sexual dimorphism while tropical non-migratory species such as this do not? I understand that dimorphism is advantageous to migratory birds who must find new mates each year, while resident species that remain paired throughout the season do not find selective advantage in having males differ from females. But why do both sexes have a bright male-like plumage when predator avoidance should favor drab appearance? Any thoughts?
Технічна інформація
- Модель
- Canon PowerShot SX70 HS
- ISO
- 250
- Фокусна відстань
- 247 mm
- Спалах
- Flash did not fire
- f-stop
- f/6.5
- Витримка
- 1/400 sec
- Розміри
- 1024 pixels x 853 pixels
- Розмір вихідного файлу
- 365.1 KB