The phrase means that the bird's barred or covered face becomes her identity mask for recognition. Reference to Context 1. A few leaves yellowing, all its seeds fallen Till the goldfinch comes, with a twitching chirrup A suddenness, a startlement, at a branch end.

The leaves of the Laburnum tree turned yellow.

The changing color of leaves is a common occurrence in many deciduous trees, including the Laburnum tree. The process of leaves turning yellow is known as leaf senescence, which happens as a part of the natural life cycle of the tree.

Why do leaves turn yellow?

1. Chlorophyll breakdown: Chlorophyll, the pigment responsible for the green color of leaves, is crucial for photosynthesis. As autumn approaches, the Laburnum tree starts to prepare for winter by breaking down chlorophyll molecules. This breakdown exposes other pigments, such as carotenoids, which give leaves their yellow color.

2. Reduced chlorophyll production: As temperatures drop and sunlight decreases, Laburnum trees slow down their chlorophyll production. This decline in chlorophyll synthesis leads to a decrease in the green color of leaves and an increase in yellow pigments.

3. Leaf senescence: Senescence is a natural aging process in plants where they shed their old leaves in preparation for new growth. During this process, nutrients are withdrawn from the leaves and stored in the tree for future use. As a result, the leaves gradually change color from green to yellow before they eventually fall off.

Impact of environmental factors:
Environmental factors, such as temperature and light, can influence the timing and intensity of leaf color change. Cooler temperatures and shorter days can accelerate the process, causing the Laburnum tree's leaves to turn yellow earlier in the season.

Conclusion:
In conclusion, the leaves of the Laburnum tree turn yellow as a result of the breakdown of chlorophyll, reduced chlorophyll production, and the natural process of leaf senescence. This change in color is a normal part of the tree's life cycle and prepares it for the dormant winter period before new leaves emerge in the spring.

How was the tree standing in the month of September?