Rake tasks fail to log when running in production mode

how-to-reproduce.sh

# generate a fresh app
rails -v
rails new whizbang
cd whizbang

# show empty log file
cat log/production.log 

# script/runner successfully writes to the log file
./script/rails runner 'Rails.logger.error("Hello from script/runner")' -e production
cat log/production.log 

# rake tasks don't write to the log file
vim lib/tasks/logging.rake
cat lib/tasks/logging.rake 
cat /dev/null > log/production.log
cat log/production.log 
RAILS_ENV=production rake logging:example
cat log/production.log 

logging.rake

namespace :logging do
  task :example => [:environment] do
    Rails.logger.error("Hello from rake")
  end
end

script-with-output

[tmp] # generate a fresh app
[tmp] rails -v
Rails 3.0.7
[tmp] rails new whizbang
      create  
      create  README
      create  Rakefile
      ...
[tmp] cd whizbang
/tmp/whizbang
[whizbang] 
[whizbang] # show empty log file
[whizbang] cat log/production.log 
[whizbang] 
[whizbang] # script/runner successfully writes to the log file
[whizbang] ./script/rails runner 'Rails.logger.error("Hello from script/runner")' -e production
[whizbang] cat log/production.log 
Hello from script/runner
[whizbang] 
[whizbang] # rake tasks don't write to the log file
[whizbang] vim lib/tasks/logging.rake
[whizbang] cat lib/tasks/logging.rake 
namespace :logging do
  task :example => [:environment] do
    Rails.logger.error("Hello from rake")
  end
end

[whizbang] cat /dev/null > log/production.log
[whizbang] cat log/production.log 
[whizbang] RAILS_ENV=production rake logging:example
(in /private/tmp/whizbang)
[whizbang] cat log/production.log 
[whizbang]