August 09, 2025

Birds Know That Summer is Ending Soon

 Here we are enjoying summer warmth, but other species know that ideal weather is ending soon.

How do I know this?

Birds have started to head south now in large numbers.

 One way I monitor bird migration is through weather radar, which picks up the movement of birds, with migration generally more evident at night.

For example, the radar this evening "lit up" with echoes after sunset....and this isn't rain.... It's birds (see below).

And by using the Doppler capabilities of the radars, we can determine the direction of flight.....to the south.   Here is a recent Doppler velocity image from the Camano Island radar:

Green indicates the target is approaching, red means moving away.  Thus, this Doppler radar image suggests movement to the south or southwest.

Then there is the BirdCast website, which heavily uses weather radar as a potent tool (below).  Lots of southward movement over the West.


Finally, the birds will have very nice flying weather for the next few days.   A significant ridge of high pressure has developed offshore (see map for 5 PM Sunday) that will bring warm, but not too warm, conditions over western Washington (mid-80s).


But this pattern won't last, and next weekend looks cooler with a chance of precipitation.


14 comments:

  1. This is fascinating even while a bit disappointing. Thank you for sharing!

    ReplyDelete
  2. Is it normal for migrations to start this early and can this indicate if birds know it's going to be a colder fall/winter?

    ReplyDelete
  3. The Swainson's thrush have gone nearly silent, as have the grosbeaks. A few Canada Jays have stopped by to compete for suet with the resident Stellars, but they seem rather quiet. The silence comes every year, but it's still strange.

    ReplyDelete
  4. Plus the jays are back where I live and they always disappear for the summer in May or June before returning in the fall. When they come back I always know summer is ending.

    ReplyDelete
  5. I love this application of weather technology Cliff! Thanks for showing us this.

    ReplyDelete
  6. Hello Professor Mass. Thank you for this blog. I have followed it for years and always appreciate the information you provide. I recently spent five months in the south of France. Nice to be exact. I wished that I had a French version of your blog to make sense of the very confusing weather there. It is extremely humid in the summer which I did not expect and although the radar says it will rain, it doesn't. The temperature and weather seem to be impossible to predict . One day, if you feel like sharing what you know about that area, it would be greatly appreciated. Merci beaucoup.

    ReplyDelete
  7. Thanks Cliff.
    The College of the Sciences at CWU entertains grade school kids and their parents with an annual event called “Nature of Night”. Last November, I volunteered to cut bird silhouettes with Audubon members on Thursday and help with the event on Saturday. The birds were taped to the ceiling of large room (dark inside) and we led groups in with flashlights to view “the overhead migrations” underway in the night sky. Kids were given flashlights, and they were asked to find the birds and count them. Meanwhile the leaders could talk about the shapes of wings, tails, and the thousands of birds migrating south.

    ReplyDelete
  8. Its amazing that so many birds are already hitting the skies and leaving our region for the winter. Is this a sign that fall is going to be colder this year? This summer, at least at the coast, has been noticeably cooler than in years past.

    ReplyDelete
  9. I once had the privilege of seeing Robins migrate, not something you get to see often I was traveling in South Dakota in the late fall between Vermilion and Yankton, (SE corner of stare) and I caught a glimpse of them flying quite high, very fast and a lot of them straight south, They were not lazy about it

    ReplyDelete
  10. It looks the overnight low recorded at Sea-Tac was right around 70. How unusual is a low temperature that high here? It seems unusually high.

    ReplyDelete
  11. Hot and humid weather out there by Western Washington standards - I'm sympathetic to those without air conditioning during heat waves such as this where overnight cooling is insufficient to provide much relief. Fortunately, it appears this will be a relatively short duration event and the current forecast indicates that toward the end of the week we can look forward to what will be the most significant precipitation event for the region since since the beginning of summer.

    ReplyDelete
  12. One of the more interesting local features are the species that experience summertime leafdrop. To cope with summer drought, certain trees shed weaker (often discolored) leaves, and it kind of gives the landscape a fall-like look, even if the process is completely different.

    ReplyDelete
  13. It was a full moon two days ago, August 9th. There is a timeless saying in Japan that Fall begins with the first full moon in August. Looks like the old adage holds. Also, lots of leaves fell last weekend when there was some wind and moisture.

    ReplyDelete
  14. I don't necessarily need birds flying south to let me know it's nearing the end of summer. I can often tell by the way the sun is as it gets lower in the sky and the air gets dusty. This causes the sun to have a slight yellowish cast. Always been aware of it (sensitive if you will to it) to let it be known that it's late summer.

    As far as temps are concerned, this summer has not been as warm it often is in recent summers. Feels more average as we've mostly stayed in the mid 70's to mid 80's as you say. Only a couple of days where my house got quite toasty, and that was early in the summer, the rest of the time, it's been mostly OK, outside of the rain we had last week on Wednesday. It was a nice change, even for just one day.

    Now just looking forward to fall in about a month.

    ReplyDelete

Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

Microscale Temperature Variations During the Summer

Have you ever experienced an unexpected breeze of cool air during an evening stroll after a warm day--like yesterday or today? On such eveni...