Amazon has added 120,000 workers. UPS is bumping its workforce up by 95,000. Toys R Us is adding 40,000 jolly elves.

That’s some serious hustle and bustle.

Fully one-third of companies across all industries in the United States hire seasonal help for the holidays. That’s good news for unemployed individuals who are looking for a temporary respite, and for employees who would like to put a little bump in their bank accounts.

It also can be absolutely fantastic news for hiring managers who will be looking to fill open positions at some point in the new year, because it offers an opportunity to evaluate potential employees. All too often, however, HR professionals are too busy with all the extra paperwork involved in seasonal hiring to scout seasonal workers for potential new talent.

Here’s why HR pros should keep their eyes open during the holidays:

1. Seasonal work is a tryout that workers don’t realize is a tryout. Most workers recognize that employers often must take whatever seasonal help they can get, and, of course, that their employment is temporary by definition. That doesn’t mean most seasonal employees won’t work hard, but it does mean there is precious little incentive to go above and beyond the call of duty. Those who do jump higher are demonstrating that they don’t need incentives to be stellar workers — it’s simply who they are. That’s exactly the sort of long-term employee every business wants.

2. People who take on seasonal work as a second job are missing something from their first. If your first job gives you all the satisfaction (and pay) you need to be content, you’re not likely to take on a second temp job. So superior seasonal workers who have a primary job might be amenable to a better situation — even if they don’t realize it themselves. This is an opportunity to identify great workers who are ripe for being lured away from their current employers.  

3. Seasonal work amounts to risk-free on-the-job training. While many employers set probationary periods for new hires in which continuing employment is contingent on meeting expectations, the meta-expectation in almost all cases — both on the part of the employer and the employee — is one of assumed permanence. Moreover, probationary periods are usually guided by specific expectations. (Essentially: “As long as you don’t break these rules, you’ve got a job here.”) The problem is that sometimes employees are simply not a great fit, even if they are technically fulfilling all their probationary duties. Seasonal hires offer a more flexible opportunity for evaluation and on-the-job training without the expectation of permanence.

4. Seasonal workers can be non-traditional gems. Qualifications for new hires are often relaxed, at least a bit, for seasonal workers. Some employers, for instance, will immediately pass on a potential employee with a felony record, but don’t consider past mistakes to be disqualifying for seasonal employees. That creates a great opportunity for business leaders to evaluate employees they might really like to hire without the floodgate-opening impact of changing long-held hiring rules.