This week many central Texas researchers have been reporting golden-cheeked warbler fledglings.  Fortunately, I was able to locate two fledgling groups myself.  One fledgling was directly above me at one of my point counts.  The only reason why I noticed it was that the male was in the tree feeding it as I approached.  Upon my arrival at the point he departed, but the fledgling remained.  It was only a few days post fledging, and at that age they don't move around much.  The second fledgling I found was just off of Warbler Vista Trail and was being feed by the female.  Typically, the male and female will split the brood when feeding their offspring, as both of these had.  One of the reasons for providing this post is so that folks recognize this time of year warblers are especially sensitive to disturbance.  Should you see a fledgling please don't approach too closely.  After all, this is their home.  I have attached a photo of the fledgling I saw at Warbler Vista Trail.  The photo I took was from a respectable distance, but due to photo cropping, it appears I am much closer.  Photos of fledglings are rare, so enjoy.  If you want to see/hear a warbler, you should go hiking soon.  As the season progresses they tend to get much quieter.  I have already noticed a significant reduction in the amount they are singing.

How many golden-cheeked warblers and black-capped vireos are on Balcones Canyonlands NWR? That's a tough question. Because singing territorial males of both species are relatively easy to find, our estimates are typically based on the number of territorial males. We know that researchers identified more than 90 black-capped vireo territories each of the last two years and some were certainly missed, so I think a conservative estimate for black-capped vireos is 100 territorial males. As for golden-cheeked warblers, our best estimate comes from former refuge biologist Chuck Sexton who estimated about 800 territorial males in 2010. 

     Recent scholarly papers have shown that population estimates of golden-cheeked warblers using the best methods are usually not very good. However, we think we can do a much better job estimating how much of the refuge is occupied by these species. Thus, I have been working with Scott Rowin, Roland Davis, Emily Haeuser, David Morgan, and Susanne Shipper to determine presence, or occupancy, of these species on the refuge. Today we are completing our second survey of each of 250 points located randomly across the refuge. We will survey each point two more times. These surveys will provide a robust estimate of occupancy across the refuge and allow us to see how things like canopy cover, canopy height, and other habitat features are related to the probability of occurrence. And, as the refuge continues to grow habitat for these species, we will have reliable estimates of how our management has affected the proportion of the refuge that is occupied by territorial males. We think we are on the right track and look forward to seeing if the birds agree.

While some biologists are out following golden-cheeked warblers and black-capped vireos to try to find their nests, our Deputy Refuge Manager, David Maple, has one-upped us by finding the biggest nest of the year. And, I do not think that his record will be beat. David found the first pig nest of his career. And to top that off, he found a second one the same day about a quarter mile away. You can see video of a domestic free-ranging pig nest at http://youtu.be/yzjfuE4rwSc. Neither of us even realized that wild pigs made nests until recently. However, when I was a kid we had a pig, Grunt, that made a nest with hay that we put in her pen. The nest in this picture taken by David is 4-5 feet in diameter and made from grass.

Field biologists surveying golden-cheeked warblers on the refuge discovered one with a nest yesterday. This may be the earliest documented nesting of golden-cheeked warblers ever! When I got out on Wednesday I found the males were very vocal, picking them up at several locations both in the morning and late afternoon. For those lacking a bird guide with audio, you can listen to recordings of golden-cheeked warbler songs at http://macaulaylibrary.org/search?location_id=&location_type_id=&location=&recordist=&recordist_id=&catalogs=&behavior=&behavior_id=&tab=audio-list&taxon_id=12000468&taxon_rank_id=67&taxon=golden+cheeked+warbler.

As I walked between our offices this morning, my nose did a double take at the sweet smell in the air. I followed the scent to the corner of the building where agarita was blooming. What a magnificent aroma! I hope you get a chance to get out and smell this delightful flower.

Sorry I have not posted in awhile.  It has been busy here a the Refuge and it seems the only time I get out in the field is to help check hog traps.  Over the past couple months I have drafted a feral and invasive animal control plan, and supporting environmental assessment.  I hope to have it done before spring.  Jim and I have also been evaluating our past warbler and vireo surveys to make sure we are spending our time as efficiently and effectively as possible.  It is likely we will switch gears this year to look at warbler and vireo occupancy and abundance across the Refuge.  This would be done with a series of point counts across the entire refuge and would be completed every 3-5 years to determine the rate of occupancy (% of Refuge occupied) by each species.  Obviously, the hope is that with time more and more of the Refuge is occupied.  This is something that we could identify as a goal for the Refuge and include in the Habitat Management Plan, another document I am working on...  Speaking of surveys, please check out the Refuge's annual report for both species.  This report is attached and details the work we did last year and also provides some basic analysis of current and past data.

2011 BCNWR GCWA and BCVI Annual Report.pdf

With low temperatures in the 50’s and 60’s this week, it is hard to believe that last year on February 1 the 24-hour period began at 62°F and ended at 15°F with wind gusts of over 50 MPH that uprooted junipers near my house. February is starting much calmer this year. Cricket frogs are already chorusing. A wild turkey gobbler was practicing his strutting before a flock of hens near Oatmeal this morning. DOR (dead-on-road) skunks are beginning to litter the roads, a sign that the males are increasing their activity as breeding season begins. The birds are singing and the fish are biting. Whatever your passion, take advantage of the great weather and get outside.

The Balcones fire crew conducted a prescribed burn on the Doeskin Ranch public use area last week. The public has a great opportunity to come take pictures of this area as it changes from bleak and blackened today to a lush landscape this spring. Unlike last year, adequate soil moisture should result in a quick green up this spring.