Huge Number (thousands) of Birds
I would like a better understanding regarding the huge number (thousands) of birds (assume migratory) that are in my backyard trees during the past several weeks. The birds are extremely noticeable (deafening sound/skyline is black with birds) at dusk. Could you provide information concerning this issue - especially how long we should expect the birds to remain?
Prince George's County Maryland
Wintertime can see many resident birds forming larger flocks (and mixed-species flocks) than they would in summer. Since they are not competing for nesting territory this time of year, they are more tolerant of crowding. Plus, the crowds bring the benefits of more eyes and ears for better detection of predators and an easier time finding sources of food. Some birds will even huddle overnight to insulate themselves on cold winter nights.
It's hard to say which birds you have without photographs, but European Starlings, Crows, and Blackbirds (a lumped group of several mostly-black birds including Starlings) are known to live in large winter flocks in our area: https://extension.umd.edu/hgic/topics/blackbirds
As the article suggests, tolerance of their presence or repeated harassment are the only recourses to hosting such flocks in our neighborhoods. There may be a reason they prefer your backyard trees over other sites, but discerning what those traits are (and what changes would motivate them to move on) would be difficult. Similarly, there may not be much you can do to alter its attractiveness to the birds without being a detriment to the plants they're roosting in.
You could try contacting the nuisance wildlife hotline (run jointly by the USDA and DNR) to ask if harassment of these birds is suggested and permitted under the Migratory Bird Act. This is their general page on wildlife issues and includes the contact number and hours of operation: https://dnr.maryland.gov/wildlife/Pages/plants_wildlife/wildlifeproblems.aspx
As we approach nesting season in a couple more months, the flock birds will disperse as they set up nesting territories.
Thanks so much for your advice. Now I have a better understanding of the migratory birds that have taken up temporary residence in my backyard. I live in Bowie and have thick bamboo in the furthest point of my yard, which is where they have roosted. The noise and the droppings (especially the droppings) are a bit much. However, we'll need to tolerate the situation. As you indicated, they should move on within the next couple months and we just need to be patient. Possibly our guests won't return next year. If they should, we will once again need to tolerate and exhibit patience.